Magnonics for configurable electronics

Read an article today in ScienceDaily on [a] New way to write magnetic info … that discusses research done at Imperial College Of London that used a magnetic force microscope (small magnetic probe) to write magnetic fields onto a dense array of nanowires.

Frustrated metamaterials needed

The original research is written up in a Nature article Realization of ground state in artificial kagome spin ice via topological defect driven magnetic writing  (paywall). Unclear what that means but the paper abstract discusses geometrically frustrated magnetic metamaterials.  This is where the physical size or geometrical properties of the materials at the nanometer scale restricts or limits the magnetic states that material can exhibit.

Magnetic storage deals with magnetic material but there are a number of unique interactions of magnetic material when in close (nm) proximity to one another and the way nanowire geometrically frustrated magnetic metamaterials can be magnetized to different magnetic moments which can be exploited for other uses.  These interactions and magnetic moments can be combined to provide electronic circuitry and data storage.

I believe the research provides a proof point that such materials can be written, in close proximity to one another using a magnetic force microscope.

Why it’s important

The key is the potential to create  magnonic circuitry based on the pattern of moments writen into an array of nanowires. In doing so, one can fabricate any electrical circuit. It’s almost like photolithography but without fabs, chemicals, or laser scanners.

At first I thought this could be a denser storage device, but the potential is much greater if electronic circuitry could be constructed without having to fabricate semiconductors. It would seem ideal for testing out circuitry before manufacturing. And ultimately if it could be scaled up, the manufacture/fabrication of electronic circuitry itself could be done using these techniques.

Speed, endurance, write limits?

There was no information in the public article about the speed of writing the “frustrated magnetic metamaterials”. But an atomic force microscope can scan 150×150 micrometers in several minutes. If we assume that a typical chip size today is 150×150 mm, then this would take 1E6 times several minutes, or ~2K days. With multiple scanning force microscopes operating concurrently we could cut this down by a factor of 10 or 100 and maybe someday 1000. 2 days to write any electronic circuit on the order of todays 23nm devices with nanowires and magnetic force microscopes would be a significant advance

Also there was no mention of endurance, write limits or other characteristics we have learned to love with Flash storage. But the assumption is that it can be written multiple times and that the pattern stays around for some amount of time.

How magnetics generate electronic circuits

Neither Wikipedia page, the public article or the paywall articles’ abstract describes how Magnonics can supply electronic circuitry. However both the abstract and the public article discuss applications for this new technology in hardware based neural networks using arrays of densely packed nanowires.

Presumably, by writing different magnetic patterns in these nanowire metamaterials, such patterns can be used to simulate hardware connected neurons. This means that the magnetic information can be overwritten because it can be trained. Also, such magnetic circuits can be constructed to: a) can create different path for electrons to flow through the material; b) can restrict or enhance this electronic flow, and c) can integrate across a number of inputs and determine how electronic flow will proceed from a simulated neuron.

If magnonics can do all that,  it’s very similar to electronic gates today in CPU, GPUs and other electronic circuitry. Maybe it cannot simulate every gate or electronic device that’s found in todays CPUs but it’s a step in the right direction. And magnonics is relatively new. Silicon transistors are over 70 years old and the integrated circuit is almost 60 years old. So in time, magnonics could very well become the next generation of chip technology.

Writing speed is a problem. Maybe if they spun the nanowire array around the magnetic force microscope…

Comments?

Photo Credits:  Real space observation of emergent magnetic monopoles … Nature article

Realization of ground state in artificial kagome spin ice via topological defect driven magnetic writing, Nature article

 

Scratch file use in HPC @ORNL, a statistical analysis

Attended SC17 (Supercomputing Conference) this past week and I received a copy of the accompanying research proceedings. There are a number of interesting papers in the research and I came across one, Scientific User Behavior and Data Sharing Trends in a Peta Scale File System by Seung-Hwan Lim, et al from Oak Ridge National Laboratory (ORNL) and the use of files at the Oak Ridge Leadership Computing Facility (OLCF) which was very interesting.

The paper statistically describes the use of a Scratch files in a multi PB file system (Lustre) at OLCF from January 2015 to August 2016. The OLCF supports over 32PB of storage, has a peak aggregate of over 1TB/s and Spider II (current Lustre file system) consists of 288 Lustre Object Storage Servers, all interconnected and connected to all the supercomputing cluster of  servers via an InfiniBand network. Spider II supports all scratch storage requirements for active/queued jobs for the Titan (#4 in Top 500 [super computer clusters worldwide] list) and other clusters at ORNL.

ORNL uses an HPSS (High Performance Storage System) archive for permanent storage but uses the Spider II file system for all scratch files generated and used during supercomputing applications.  ORNL is expecting Spider III (2018-2023) to host 10 billion files.

Scratch files are purged from Spider II after 90 days of no access.The paper is based on metadata analysis captured during scratch purging process for 500 days of access.

The paper displays a number of statistics and metrics on the use of Spider II:

  • Less than 3% of projects have a directory depth >15, the maximum directory depth was recorded at 432, with most projects having a shallow (<10) directory depth.
  • A project typically has 10X the files that a specific researcher has and a median file count/researcher is 2000 files with a median project having 20,000 files.
  • Storage system performance is actively managed by many projects. For instance, 20 out of 35 science domains manually managed their Lustre cluster configuration to improve throughput.
  • File count continues to grow and reached a peak of 1B files during the time being analyzed.
  • On average only 3% of files were accessed readonly, 10% of files updated (read-write) and 76% of files were untouched during a week period. However, median and maximum file age was 138 and 214 days respectively, which means that these scratch files can continue to be accessed over the course of 200+ days.

There was more information in the paper but one item missing is statistics on scratch file size distribution a concern.

Nonetheless, in paints an interesting picture of scratch file use in HPC application/supercluster environments today.

Comments?

Crowdresearch, crowdsourced academic research

Read an article in Stanford Research, Crowdsourced research gives experience to global participants that discussed an activity in Stanford and other top tier research institutions to try to get global participation in academic research. The process is discussed more fully in a scientific paper (PDF here) by researchers from Stanford, MIT Media Lab, Cornell Tech and UC Santa Cruz.

They chose three projects:

  • A HCI (human computer interaction) project to design, engineer and build a new paid crowd sourcing marketplace (like Amazon’s Mechanical Turk).
  • A visual image recognition project to improve on current visual classification techniques/algorithms.
  • A data science project to design and build the world’s largest wisdom of the crowds experiment.

Why crowdsource academic research?

The intent of crowdsourced research is to provide top tier academic research experience to persons which have no access to top research organizations.

Participating universities obtain more technically diverse researchers, larger research teams, larger research projects, and a geographically dispersed research community.

Collaborators win valuable academic research experience, research community contacts, and potential authorship of research papers as well as potential recommendation letters (for future work or academic placement),

How does crowdresearch work?

It’s almost an open source and agile development applied to academic research. The work week starts with the principal investigator (PI) and research assistants (RAs) going over last week’s milestone deliveries to see which to pursue further next week. The crowdresearch uses a REDDIT like posting and up/down voting to determine which milestone deliverables are most important. The PI and RAs review this prioritized list to select a few to continue to investigate over the next week.

The PI holds an hour long video conference (using Google Hangouts On Air Youtube live stream service). On the conference call all collaborators can view the stream but only a select few are on camera. The PI and the researchers responsible for the important milestone research of the past week discuss their findings and the rest of the collaborators on the team can participate over Slack. The video conference is archived and available  to be watched offline.

At the end of the meeting, the PI identifies next weeks milestones and potentially directly responsible investigators (DRIs) to work on them.

The DRIs and other collaborators choose how to apportion the work for the next week and work commences. Collaboration can be fostered and monitored via Slack and if necessary, more Google live stream meetings.

If collaborators need help understanding some technology, technique, or too, the PI, RAs or DRIs can provide a mini video course on the topic or can point to other information used to get the researchers up to speed. Collaborators can ask questions and receive answers through Slack.

When it’s time to write the paper, they used Google Docs with change tracking to manage the writing process.

The team also maintained a Wiki on the overall project to help new and current members get up to speed on what’s going on. The Wiki would also list the week’s milestones, video archives, project history/information, milestone deliverables, etc.

At the end of the week, researchers and DRIs would supply a mini post to describe their work and link to their milestone deliverables so that everyone could review their results.

Who gets credit for crowdresearch?

Each week, everyone on the project is allocated 100 credits and apportions these credits to other participants the weeks activities. The credits are  used to drive a page-rank credit assignment algorithm to determine an aggregate credit score for each researcher on the project.

Check out the paper linked above for more information on the credit algorithm. They tried to defeat (credit) link rings and other obvious approaches to stealing credit.

At the end of the project, the PI, DRIs and RAs determine a credit clip level for paper authorship. Paper authors are listed in credit order and the remaining, non-author collaborators are listed in an acknowledgements section of the paper.

The PIs can also use the credit level to determine how much of a recommendation letter to provide for researchers

Tools for crowdresearch

The tools needed to collaborate on crowdresearch are cheap and readily available to anyone.

  • Google Docs, Hangouts, Gmail are all freely available, although you may need to purchase more Drive space to host the work on the project.
  • Wiki software is freely available as well from multiple sources including Wikipedia (MediaWiki).
  • Slack is readily available for a low cost, but other open source alternatives exist, if that’s a problem.
  • Github code repository is also readily available for a reasonable cost but  there may be alternatives that use Google Drive storage for the repo.
  • Web hosting is needed to host the online Wiki, media and other assets.

Initial projects were chosen in computer science, so outside of the above tools, they could depend on open source. Other projects will need to consider how much experimental apparatus, how to fund these apparatus purchases, and how a global researchers can best make use of these.

My crowdresearch projects

Some potential commercial crowdresearch projects where we could use aggregate credit score and perhaps other measures of participation to apportion revenue, if any.

  • NVMe storage system using a light weight storage server supporting NVMe over fabric access to hybrid NVMe SSD – capacity disk storage.
  • Proof of Stake (PoS) Ethereum pooling software using Linux servers to create a pool for PoS ETH mining.
  • Bipedal, dual armed, dual handed, five-fingered assisted care robot to supply assistance and care to elders and disabled people throughout the world.

Non-commercial projects, where we would use aggregate credit score to apportion attribution and any potential remuneration.

  • A fully (100%?) mechanical rover able to survive, rove around, perform  scientific analysis, receive/transmit data and possibly, effect repairs from within extreme environments such as the surface of Venus, Jupiter and Chernoble/Fukishima Daiichi reactor cores.
  • Zero propellent interplanetary tug able to rapidly transport rovers, satellites, probes, etc. to any place within the solar system and deploy theme properly.
  • A Venusian manned base habitat including the design, build process and ongoing support for the initial habitat and any expansion over time, such that the habitat can last 25 years.

Any collaborators across the world, interested in collaborating on any of these projects, do let me know, here via comments. Please supply some way to contact you and any skills you’re interested in developing or already have that can help the project(s).

I would be glad to take on PI role for the most popular project(s), if I get sufficient response (no idea what this would be). And  I’d be happy to purchase the Drive, GitHub, Slack and web hosting accounts needed to startup and continue to fruition the most popular project(s). And if there’s any, more domain experienced PIs interested in taking any of these projects do let me know.  

Comments?

Picture Credit(s): Crowd by Espen Sundve;

Videoblogger Video Conference by Markus Sandy;

Researchers Night 2014 by Department of Computer Science, NTNU;

A steampunk Venusian rover

Read an article last week in theEngineer on “Designing a mechanical rover to explore … Venus“, on a group at JPL, led by Jonathon Sauder who are working on a mechanical rover to study Venus.

Venus has a temperature of ~470c, hot enough to melt lead, which will fry most electronics in seconds. Moreover, the Venusian surface is under a lot of pressure, roughly equivalent to a mile under water or ~160X the air pressure at Earth’s surface (from NASA Venus in depth). Extreme conditions for any rover.

Going mobile

Sauder and his team were brainstorming mechanical rovers, that operated similar to Theo Jansen’s StrandBeest which walks using wind energy alone. (Checkout the video of the BEEST walking).

Jansen had told Sauder’s team that his devices work much better on smooth surfaces and that uneven, beach like surfaces presented problems.

So, Sauder’s team started looking at using something with tracks instead of legs/feet, sort of like a World War 1 tank. That could operate upside down as well as rightside up.

Rather than sails (as the StrandBeest), they plan to use multiple vertical axis wind turbines, called Sarvonius rotors, located inside the tank to create energy and store that energy in springs for future use.

Getting data

They’re not planning to ditch electronics all together but need to minimize the rovers reliance on electronics.

There are some electronics that can operate at 450C based on silicon carbide and gallium carbide which have a very low level of integration at this time, just a 100 transistors per chip.  And they could use this to add electronic processing and control to their mechanical rover.

Solar panels can supply electricity to the high temperature electronics and can operate at 450C.

But to get information off the rover and back to the Earth, they plan to use a highly radio reflective spot on the rover and a mechanical shutter mechanism. The mechanism can be closed and opened and together with an orbiting satellite generating radio pulses and recording the rover’s reflectivity or not, send Morse code from rover to satellite. The orbiting satellite could record this information and then transmit it to Earth.

The rover will make use of simple chemical reactions to measure soil, rock and atmospheric chemistry. Soil and rocks suitable for analysis can be scooped up, drilled out and moved to the analysis chamber(s) via mechanical devices. Wind speed and direction can be sensed with simple mechanical devices.

In order to avoid obstacles wihile roving around the planet, they  plan to use a mechanical probe out othe front (and back?) of the rover with control systems attached to this to avoid obstacles. This way the rover can move around more of the planets surface.

Such a mechanical rover with high temperature electronics might also be suitable for other worlds in the solar system, Mercury for sure but moons of the Jovian planets, also have extreme pressure environments.

And such a electrical-mechanical rover also might work great to probe volcano’s on earth, although the temperatures are 700 to 1200C, ~2 to 3X Venus. Maybe such a rover could be used in highly radioactive environments to record information and send this back to personnel outside the environment or even effect some preprogrammed repairs. Ocean vents could also be another potential place where such a rover might work well.

Possible improvements

Mechanical probes would need to be moved vertically and swing horizontally to be effective and would necessarily have to poke outside the tanks envelope to read obstacles ahead.

Sonar could work better. Sounds or clicks could be produced mechanically and their reflections could be also received mechanically (a mic is just a mechanical transducer). At the pressures on Venus, sound should travel far.

Morse code was designed to efficiently send alpha-numerics and not much else. It would seem that another codec could be designed to send scientific information faster. And if one mechanical spot is good, multiple spots would be better assuming the satellite could detect multiple radio reflective spots located in close proximity to one another on the rover.

Radio works but why not use infrared. If there were some way to read an infrared signal from the probe, it could present more information per pass.

For instance, an infrared photo of the rover’s bottom or top, using with a flat surface, could encode information in cold and hot spots located across that surface.

This could work at whatever infrared resolution available from the satellite orbiting overhead and would send much more information per orbital pass.

In fact, such an infrared surface readout might allow the rover to send B&W pictures up to the satellite. Sonar could provide a mechanism to record a (sound) picture of the environment being scanned. The infrared information could be encoded across the surface via pipes of cool and hot liquids, sort of like core memory of old.

What about steam power. With 450C there ought to be more than enough heat to boil some liquid and have it cool via expansion. Having cool liquid could be used to cool electronics, chemical and solar devices.  And as the high temperatures on Venus seem constant, steam power and liquid cooling would be available all the time and eliminating any need for springs to hold energy.

And the cooling liquid from steam engines could be used to support an infrared signaling mechanism.

Still not sure why we need any electronics. A suitably configured, shrunken, analytical engine could provide the rudimentary information processing necessary to work the shutter or other transmitter mechanisms, initiate, readout and store mechanical/chemical/sonar sensors and control the other items on the rover.

And with a suitably complex analytical engine there might be some way to mechanically program it with various modes using something like punched tape or cards. Such a device could be used to hold and load information for separate programs in minimal space and could also be used to store information for later transmission, supplying a 100% mechanical storage device.

Going 100% mechanical could also lead to a potentially longer lived rover than something using some electronics and mostly mechanical devices on a planet like Venus. Mechanical devices can fail, but their failure modes are normally less catastrophic, well understood. Perhaps with sufficient mechanical redundancy and concern for tribology, such a 100% mechanical rover could last an awful long time, without any maintenance, e.g., like swiss watches.

Comments?

Photo Credit(s): World War One tank – mark 1 by Photos of the Past

Vintage Philmor morse code practice … by Joe Haupt

Accompanied by an instructor… by vy pham;

Core memory more detail by Kenneth Moore;

Model of the Analytical Engine By Bruno Barral (ByB), CC BY-SA 2.5;

Punched tape by Rositslav Lisovy

Steam locomotives by Jim Phillips

Two paths to better software

Read an article last week in the Atlantic, The coming software apocalypse, about some of the problems in how we develop software today.

Most software development today is editing text files. Some of these text files have 1,000s of lines and are connected to other text files with 1,000s of more lines which are connected to other text files with 1,000s of lines, etc. Pretty soon you have millions of lines of code all interacting with one another.

The problem

Been there done that and it’s not pretty. We even spent some time trying to reduce the code bloat by macro-izing some of it, and that just made it harder to understand, but reduced the lines of code.

The problem is much worse now where . we have software everywhere you look, from the escalator-elevator you take up and down between floors, to the cars you drive around town, to the trains and airplanes you travel between cities.

All of these literally have millions of lines of code controlling them and are many more each year. How can they all possibly be correct.

Well you can test the s&*t out of them. But you can’t cover every path in a lifetime or ten of testing a million line program. And even if you could, changing a single line would generate another 100K or more paths to test. So testing was never a true answer.

Two solutions

The article talks about two approaches that have some merit to solve the real problem.

  • Model based development, a new development and coding environment. In this approach your not so much coding as playing with a model of the behavior your looking for. Say you were coding robot control logic, rather than editing 1000s of lines of Java text, you work with a model of your robot and its environment on 1/2 a screen and on the other half, model parameters (dials, sliders, arrow keys, etc) and logic (sequences) that you  manipulate to do what the robot needs to do. Sort of like Scratch on steroids (see my post on 10 years of Scratch) with the sprite being whatever you need to code for be it a jet engine, automobile, elevator, whatever. The playground would be a realtime/real life simulation of the entity under control of the code and you would code by setting parameters  and defining sequences. But the feedback would be immediate!
  • TLA+ a formal design verification approach. Formal methods have been around since the early 70s. They are used to rigorously specify a design of  some code or a whole system. The idea is that if you can specify a  provably correct design, then the code (derived from that design) has the potential to be more correct. Yes there’s still the translation from code to design that’s error prone but the likelihood is that these errors will be smaller in scope than having a design that wrong.

Model based  development

One can find model based development already in the Apple new application development language, Swift, ANSYS SCADE suite based on Esterel Technologies, and Light Table software development environment.

I have never used any of them but they all look interesting. Esterel was developed for safety critical, real-time aerospace applications. Light Table was a kickstarter project started by a leading engineer of Microsoft’s Visual Studio, the leading IDE. Apple Swift was developed to make it much easier to develop IOS apps.

TLA+

TLA+ takes a bit getting used to. All formal methods depend on advanced mathematics and sophisticated logic and requires an adequate understanding of these in order to use properly. TLA+ was developed by Leslie Lamport and stands for temporal logic of actions.

TLA+ specifications identify the set of all correct system actions. I would call it a formal pseudo code.

There’s apparently a video course , a hyperbook and a book on the language It’s being used in AWS and Microsoft XBOX and Azure. (See the wikipedia TLA+ article for more information).

There’s PlusCal algorithm (specification) language which is translated into a TLA+ specification which can then be checked by the automated TLC model checker.  There’s also an automated TLAPS, a TLA+ proof system although it doesn’t support all of the TLA+ primitives.  There’s a whole TLA+ toolbox that has these and other tools that can make TLA+ easier to use.

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We dabbled in formal specifications methods for on our million+ line storage system at a former employer. It worked well and cleaned up a integrity critical area of the product. Alas, we didn’t expand it’s use to other areas of the product and it sort of fell out of favor. But it worked when and where we applied it.

Of course this was before automated formal methods of today, but even manual methods of specification precision can be helpful to think out what a design has to do to be correct.

I have no doubt that both TLA+ formal methods and model based development approaches and more are required to truly vanquish the coming software apocalypse.

At least until artificial intelligence starts developing all our code for us.

Comments?

Photo Credits: Six easy pieces of quantitatively analyzing open source, SAP Research;

Spaghetti code still existed, Toolbox.com;

How to write apps with Swift, MacWorld;

Modeling the dining philosophers problem in TLA+, Metadata blog

 

Compressing information through the information bottleneck during deep learning

Read an article in Quanta Magazine (New theory cracks open the black box of deep learning) about a talk (see 18: Information Theory of Deep Learning, YouTube video) done a month or so ago given by Professor Naftali (Tali) Tishby on his theory that all deep learning convolutional neural networks (CNN) exhibit an “information bottleneck” during deep learning. This information bottleneck results in compressing the information present, in for example, an image and only working with the relevant information.

The Professor and his researchers used a simple AI problem (like recognizing a dog) and trained a deep learning CNN to perform this task. At the start of the training process the CNN nodes at the top were all connected to the next layer, and those were all connected to the next layer and so on until you got to the output layer.

Essentially, the researchers found that during the deep learning process, the CNN went from recognizing all features of an image to over time just recognizing (processing?) only the relevant features of an image when successfully trained.

Limits of deep learning CNNs

In his talk the Professor identifies two modes of operations of a deep learning CNN: the encoder layers and decoder layers. The encoder function identifies relevant information in the input and the decoder function takes this relevant information and maps this to an output.

This view results in two statistics that can characterize any deep learning CNN:

  • Sample complexity which refers to the the mutual information inside the last hidden layer of the encoder function, and
  • Accuracy or generalization error, which refers to the mutual information inside the last hidden layer of the decoder function.

Where mutual information is defined as how much of the uncertainty of an input is removed when you have an output that is based on that input. (See the talk for a more formal explanation).

The professor states that any complex deep learning CNN can be characterized by these two statistics where sample complexity determines the number of samples required and accuracy determines the precision by which the deep learning CNN can properly interpret those samples. The deep black line in the chart represents the limits of accuracy achievable at some number of training events, with some number of hidden layers and some sample set.

What happens during deep learning

Moreover, the professor shows an interesting characteristic of all CNNs is that they converge over time in accuracy and that convergence differs based mostly on the number of layers, sample size and training count used.

In the chart, the top row show 3 CNNs with different amounts of training data (5%, 40% and 80% of total). The chart shows the end result and trace of learning within the CNN over the same number of epochs (training cycles). More training data generates more accurate results.

The Professor views those epochs after the farthest right traces (where the trace essentially starts moving up and to the left in the chart), the compression phase of deep learning.

Statistics of deep learning process

The professor goes on to characterize the deep learning  process by calculating the mean and variance of each layers connection weights.

In the chart he shows an standard “eiffel tower” neural network, with 6 hidden layers, each with less neurons (nodes)  than the previous layer (12 nodes, 10 nodes, 7 nodes, etc.). And what he plots is the average weights and variance between layers (red lines are average and variance of the weights for arcs[connections] between nodes in layer 1 to nodes in layer 2, blue lines the mean and variance of weights for arcs between layer 2 and 3, purple lines the mean and variance of weights for arcs between layer 3 and 4, etc.).

He shows that at the start of training the (randomly assigned) weights for each layer have a normalized mean which is higher than its normalized variance. He calls this phase as high signal to noise (I would say the opposite, its low signal to noise, more noise than signal). But as training proceeds (over more epochs), there comes a point where the layer mean drops below its variance and the signal to noise ratio changes dramatically. After that point the mean weights and variance of the group of layers start to diverge or move apart.

The phase (epochs) after the line where the weights means are lower than its variance, he calls the Compression phase of the deep layer CNN training.

The Professor suggests that every complex deep learning CNN looks the same during training if you perform the calculations. The professor shows charts like this for other deep learning CNNs used on different problems and they all exhibit some point where their means are lower than their weights after which means and variances between layers starts to differentiate.

Do layer counts and sample size matter?


It turns out that the more hidden layers you have, the sooner (less training) you need to begin the compression phase. This chart shows the same problem, with different hidden layer counts. One can see in the traces, that not only is accuracy improved with more layers but it also more quickly reaches the compression phase.

Using his sample complexity and accuracy statistics, the Professor has also shown that their are limits to the amount of accuracy to any deep learning CNN based on the function of layer counts, sample size and training event counts.

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As far as I know, The Professor and his team are the first to try to characterize and understand what happens during deep learning. In doing so, he has shown that the number of layers and the number of samples can be used to predict the speed of learning. And ultimately how accurate any deep learning CNN can be.

Comments?

Research reveals ~liquid nitrogen temperature molecular magnets with 100X denser storage


Must be on a materials science binge these days. I read another article this week in Phys.org on “Major leap towards data storage at the molecular level” reporting on a Nature article “Molecular magnetic hysteresis at 60K“, where researchers from University of Manchester, led by Dr David Mills and Dr Nicholas Chilton from the School of Chemistry, have come up with a new material that provides molecular level magnetics at almost liquid nitrogen temperatures.

Previously, molecular magnets only operated at from 4 to 14K (degrees Kelvin) from research done over the last 25 years or so, but this new  research shows similar effects operating at ~60K or close to liquid nitrogen temperatures. Nitrogen freezes at 63K and boils at ~77K, and I would guess, is liquid somewhere between those temperatures.

What new material

The new material, “hexa-tert-butyldysprosocenium complex—[Dy(Cpttt)2][B(C6F5)4], with Cpttt = {C5H2tBu3-1,2,4} and tBu = C(CH3)3“, dysprosocenium for short was designed (?) by the researchers at Manchester and was shown to exhibit magnetism at the molecular level at 60K.

The storage effect is hysteresis, which is a materials ability to remember the last (magnetic/electrical/?) field it was exposed to and the magnetic field is measured in oersteds.

The researchers claim the new material provides magnetic hysteresis at a sweep level of 22 oersteds. Not sure what “sweep level of 22 oersteds” means but I assume a molecule of the material is magnetized with a field strength of 22 oersteds and retains this magnetic field over time.

Reports of disk’s death, have been greatly exaggerated

While there seems to be no end in sight for the densities of flash storage these days with 3D NAND (see my 3D NAND, how high can it go post or listen to our GBoS FMS2017 wrap-up with Jim Handy podcast), the disk industry lives on.

Disk industry researchers have been investigating HAMR, ([laser] heat assisted magnetic recording, see my Disk density hits new record … post) for some time now to increase disk storage density. But to my knowledge HAMR has not come out in any generally available disk device on the market yet. HAMR was supposed to provide the next big increase in disk storage densities.

Maybe they should be looking at CAMMR, or cold assisted magnetic molecular recording (heard it here, 1st).

According to Dr Chilton using the new material at 60K in a disk device would increase capacity by 100X. Western Digital just announced a 20TB MyBook Duo disk system for desktop storage and backup. With this new material, at 100X current densities, we could have 2PB Mybook Duo storage system on your desktop.

That should keep my ever increasing video-photo-music library in fine shape and everything else backed up for a little while longer.

Comments?

Photo Credit(s): Molecular magnetic hysteresis at 60K, Nature article

 

Materials science rescues civilization, again

Read a bunch of articles this past week from MIT Technology Review, How materials science will determine the future of human civilization, from Stanford University, New ultra thin semiconductor materials…, and Wired, This battery breakthrough could change everything.

The message varied a bit between articles but there was an underlying theme to all of them. Materials science was taking off, unlike it ever has before. Let’s take them on, one by one, last in first out.

New battery materials

I have not reported on new battery structures or materials in the past but it seems that every week or so I run across another article or two on the latest battery technology that will change everything. Yet this one just might do that.

I am no material scientist but Bill Joy has been investing in a company, Ionic Materials, for a while now (both in his job as a VC partner and as in independent invested) that has been working on a solid battery material that could be used to create rechargeable batteries.

The problems with Li(thium)-Ion batteries today are that they are a safety risk (lithium is a highly flammable liquid) and they use an awful lot of a relatively scarce mineral (lithium is mined in Chile, Argentina, Australia, China and other countries with little mined in USA). Electric cars would not be possible today with Li-On batteries.

Ionic Materials claim to have designed a solid polymer electrolyte that can combine the properties of familiar, ultra-safe alkaline batteries we use everyday and the recharge ability of  Li-Ion batteries used in phones and cars today. This would make a cheap, safe rechargeable battery that could work anywhere. The polymer just happens to also be fire retardant.

The historic problems with alkaline, essentially zinc and manganese dioxide is that they can’t be recharged too many times before they short out. But with the new polymer these batteries could essentially be recharged for as many times as Li-Ion today.

Currently, the new material doesn’t have as many recharge cycles as they want but they are working on it. Joy calls the material ional.

New semiconductor materials

Moore’s law will eventually cease. It’s only a question of time and materials.

Silicon is increasingly looking old in the tooth. As researchers shrink silicon devices down to atomic scales, they start to breakdown and stop functioning.

The advantages of silicon are that it is extremely scaleable (shrinkable) and easy to rust. Silicon rust or silicon dioxide was very important because it is used as an insulator. As an insulating layer, it could be patterned just like the silicon circuits themselves. That way everything (circuits, gates, switches and insulators) could all use the same, elemental material.

A couple of Stanford researchers, Eric Pop and Michal Mleczko, a electrical engineering professor and a post doc researcher, have discovered two new materials that may just take Moore’s law into a couple of more chip generations. They wrote about these new materials in their paper in Science Advances.

The new materials: hafnium diselenide and zirconium diselenide have many similar properties to silicon. One is that they can be easily made to scale. But devices made with the new materials still function at smaller geometries, at just three atoms thick (0.67nm) and also consume happen less power.

That’s good but they also rust better. When the new materials rust, they form a high-K insulating material. With silicon, high-K insulators required additional materials/processing and more than just simple silicon rust anymore. And the new materials also match Silicon’s band gap.

Apparently the next step with these new materials is to create electrical contacts. And I am sure as any new material, introduced to chip fabrication will take quite awhile to solver all the technical hurdles. But it’s comforting to know that Moore’s law will be around another decade or two to keep us humming away.

New multiferric materials

But just maybe the endgame in chip fabrication materials and possibly many other domains seems to be new materials coming out of ETH Zurich Switzerland.

There a researcher, Nicola Saldi,n has described a new sort of material that has both ferro-electric and ferro-magnetic properties.

Spaldin starts her paper off by discussing how civilization evolved mainly due to materials science.

Way in the past, fibers and rosin allowed humans to attach stone blades and other material to poles/arrows/axhandles to hunt  and farm better. Later, the discovery of smelting and basic metallurgy led to the casting of bronze in the bronze age and later iron, that could also be hammered, led to the iron age.  The discovery of the electron led to the vacuum tube. Pure silicon came out during World War II and led to silicon transistors and the chip fabrication technology we have today

Spaldin talks about the other major problem with silicon, it consumes lots of energy. At current trends, almost half of all worldwide energy production will be used to power silicon electronics in a couple of decades.

Spaldin’s solution to the  energy consumption problem is multiferric materials. These materials offer both ferro-electric and ferro-magnetic properties in the same materials.

Historically, materials were either ferro-electric or ferro-magnetic but never both. However, Spaldin discovered there was nothing in nature prohibiting the two from co-existing in the same material. Then she and her compatriots designed new multiferric materials that could do just that.

As I understand it, ferro-electric material allow electrons to form chemical structures which create electrical dipoles or electronic fields. Similarly, ferro-magnetic materials allow chemical structures to create magnetic dipoles or magnetic fields.

That is multiferric materials can be used to create both magnetic and electronic fields. And the surprising part was that the boundaries between multiferric magnetic fields (domains) form nano-scale, conducting channels which can be moved around using electrical fields.

Seems to me that if this were all possible and one could fabricate a substrate using multi-ferrics and write (program) any electronic circuit  you want just by creating a precise magnetic and electrical field ontop of it. And with todays disk and tape devices, precise magnetic fields are readily available for circular and linear materials. And it would seem just as easy to use multi multiferric material for persistent data storage.

Spaldin goes on to say that replacing magnetic fields in todays magnetism centric information/storage industry with electrical fields should lead to  reduced energy consumption.

Welcome to the Multiferric age.

Photo Credit(s): Battery Recycling by Heather Kennedy;

AMD Quad Core backside by Don Scansen;  and

Magnetic Field – 14 by Windell Oskay