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The magic trick is called chip carrier How could magnetism fundamental research attract private companies and funding agencies? I wanted to share this trick with you.

Most of the basic science research is based on submitting research proposals. It is a common belief that the presence of private entities supports and/or legitimates the bold statements usually present in the introductory paragraphs: many of us shall change the world if that research project is funded. Therefore, while compiling such documents, it is strongly encouraged to attract private companies so that they become part of the consortium of institutions that will carry out the project.

If a multinational company is present, some members of the evaluation panels (likely to comprise numerous scientists) may think that the intellectual property policies of the company will create a gap between the interests of the project and the agenda of the large corporation. On the other extreme, if a regional small or medium enterprises is listed, then the panel might react in a skeptical manner to the usually big statements and promises dressing up the projects: how come such an small regional business can make a break-through in this technology?

In my opinion, the most important point is to make the evaluation team believe that the synchronization between academia and industry will work. And to be convincing on this aspect, on has to define very clearly how the interface between them will be.

Last Friday, Nature Publishing Group released an article in which the _nano_science and the _macro_applications are nicely entangled in Figure 1. As simple as it gets, our trick is to nominate the "chip carrier" as the formal meeting point of academia and industry. It is clear and specific.

Scientists are used to prepare chip carriers to carry out their experiments. On the other hands, companies are used to read the datasheet of a new component and build the electronics around it accordingly. There can't be a more natural meeting point.

Let's have a look at Figure 1 from the aforementioned article (see open-access link below): panels (a) and (b) contain the science stuff which fall beyond the limits of understanding of many industrial partners. (And remember: you won't pay attention for long to things that you do not understand.) A subtle part of panel (c) contains the chip carrier: this is so-needed for the scientific experiments but it also represents the first step (the pin-out diagrams on a datasheet) where industry begins. Isn't it beautiful? So, in your next proposal, as much as it is feasible, try to identify where is your chip carrier. If the evaluation panel understands that each block of people will do what they know and like doing and they exchange and already mutually common and existing piece.. then the synchronization should not be a problem.

Thanks for reading,
Xavi Marti


p.s.: find below the links to the articles of relevance here:

Antiferromagnetic CuMnAs multi-level memory cell with microelectronic compatibility (open-access)
https://www.nature.com/articles/ncomms15434

Antiferromagnetic spintronics (pay-wall access)
http://www.nature.com/nnano/journal/v11/n3/full/nnano.2016.18.html

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Magnetic fields that could kill you Before my visit this week to +King Abdullah University of Science and Technology, I've asked my friend +Joan Batet for advice in how to entangle the desert and the magnetism. As I expected, he is the type of globe-trotter that, ultimately, had already connected both.


+Joan Batet has crossed (behind the wheel and as a driver!) more than ten times the Sahara desert. And this is not a new hobby because he started doing that well before the GPS had become a common thing. Indeed, our adventurer was on the cover page on the issue of Adventure Travel featuring the emerging GPS technologies. Yes, emerging, I mean.. that was a long time ago!

Before the satellite era, Joan used the classic magnetic compass and a map. (anybody remembers those times?!). In our recent meeting, gathered by +Jordi Planas Manzano, Joan explained how critical was to decide where to place the compass inside the car. For the pilots comfort, it would be great to have the map and the compass on sight and ready for eye inspection without using the hands. However, the stray fields of the car could add on top of the Earth magnetic field and get you confused. In a land where many directions may look the same, confusions might be very well paid with your life.

The distortion of the compass is very similar to the effect that lets magnetoresistive technology such as EON's Spinwire detect cars successfully: the Earth has a magnetic field that, presumably, guides the compass and makes it follow the magnetic North. However, metals distort the ideal trajectory of the magnetic field lines. While in the smart city context this trick is the core idea behind vehicle detection, on the desert a tiny change on your heading can leave you starving, and thirsty - if not dead.

Therefore: beware of calibration of electronic compasses! You can do this exercise yourself: while your smartphone GPS may work perfectly while you are moving, you may experience in some units that they fail to detect where are you looking towards at a given instant. This may be a bad callibration or just that your smartphone protective enclosure has a magnetic component. Check it yourself!

Thanks for reading!

Xavi Marti
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Hierro! (Iron!) We have been studying for the last months what this chunk of magnetic stones were doing. Yes! An exhausting work where magnets and spintronics play a key role. Actually, most of the dust and stones of this volcanic paradise lost in the Atlantic ocean will stick to your smartphone case or phone chargers if they are magnetic too. More data snapshots coming in the next days!

Do you remember when we talked about detecting cars using compasses? That is the same story but here the car is a volcano and the compasses are placed around it or even in nearby islands! But, after all, nothing more than a big parking spot experiment. Exactly the same story.. but at the geological scale.

Thanks for reading,
Xavi
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A hard nut to crack In the last posts, we have been seeing how magnetism and elasticity interact in some materials. Our planet Earth is a good example of hosting these two phenomena.

Our compasses have convinced us that the Earth is sort of a magnet, right? We can go outdoor and we can get oriented because the compass points to something called the North (magnetic) Pole. However, this point is not as fixed as we think: with time, it starts to roam around and, periodically, it completely flips and lets the South (magnetic) Pole point towards Greenland. Argh!

When this happens, the cartographers have troubles and they have to reprint the arrows in the maps ;). But many geophysicists see an opportunity.

Perhaps, your hard-drives already use heat to assist the magnetic writing of information because the magnetic media in there may need something else than the proximity of a magnet (the write-head) to get the information written on it. When heated, the magnetic media becomes more sensitive to the proximity of a write-head and it is the combination of both things (heat and magnetic fields) what ultimately turns your favorite movie or your last homework assignment into stored data.

This same thing that happens at the _nano_scale happens at the _geo_scale. Yes! Volcanoes could be sort of a magnetic bit. They indeed store valuable information about our past! How is it possible?

The hot rocks, if magnetic, will be more sensitive the weak Earth's magnetic field present at a given moment. When rocks cool while exposed to magnetic field, the status of the Earth magnetic field is imprinted on the rocks. If the Earth magnetic field flips later on, the cold rocks will not follow this flip. However, some hot magnetic rocks elsewhere may. Therefore, the big deal is to hunt for the cold magnetic rocks, and read where they are pointing to. By dating the rocks and sorting out all this information, scientists can know what our beloved magnet has been playing in the past millions of years.

This phenomena became indirectly popular because it hindered the detection of metallic submarines in the ocean. We wrote a post about this long time ago: plus.google.com/+XaviMarti31415/posts/QFKEjtqPpBF


Thanks for reading!
Xavi Marti
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Walls built for free Two posts ago, we discussed that some materials prefer to transform rather than break when they are subject to stress. (Some of us do this as well!). Nature, however, is not only about white or black and many times it offers an intermediate solution to the negotiation.

Stress deforms materials and, if large enough and persistent, it can break them. But nature will not just give up without a fight. While stress is applied some materials transform. Indeed, there are some phases of some materials which are only found under stress: when all is in peace, they do not exist - they just do when there is stress going on around.

There are mechanisms to mitigate the stress. Some materials, instead of just breaking apart, they allow that some portions of them transform to better accommodate the impending stress. Occasionally, you can observe in there beautiful patterns that are formed across the material. The regions that separate the different domains are known as domain walls and they play a fundamental role in material science and many data storage technologies.

The funny aspect of this animation shown below is that the same formulas will be used in the next posts to (try to) simulate tectonic motions on the entire planet Earth. From nano to geo, that's the beauty I find in having studied physics: you end up using the same tools for a wide variety of problems!

Thanks for reading,
Xavi Marti
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A moment for the No-Magnets Several years ago, about a decade Allan MacDonald (now in Austin) mentioned in a talk at annual American Physical Society meeting the words antiferromagnetic spintronics. For many years, this proposal stayed in the fridge. Ten years later, many applications are now starting to be based on those magnets that do not get stuck on the fridge.

The path between academic research and applications is not an easy one. Even more, I believe nobody knows a magic formula to do it in each case. Therefore, each discipline requires its own tricks to make its way quicker to the market. In the attached talk, I explain one possible path to connect PDF papers with PDF invoices.

I want to thank +Greta Radaelli and +Jordi Planas Manzano to encourage me giving a TEDx talk about this. I was going to decline the offer but they both were very convincing. I am still scared because the type of talks I usually give at conferences are miles away from a good TEDx talk. Let's see!

Thanks for reading,
Xavi Marti
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Forget from nano to geo! Jordi Planas says the sky is the limit! I had the pleasure of sharing a breakfast with +Jordi Planas Manzano and +Joan Batet. We met during one of those events they both call TED, in catalan, *T*remendos *E*smorzars del *D*issabte (literally, terrific Saturday brunch). Jordi started working in the 70's assembling magnetic random access memories.

The adventures of this truly old-school entrepreneur brought Jordi to work by and for IBM, Data General, Wang, ICL, Control Data Corporation, Burroughs (the first ATM machines that reached Spain!), NCR, Univac, Honeywell Bull y Textronics and, finally, invited to participate in the design of the Space Shuttle in the second half of the 70's.

Jordi is now curating a blog reviewing those past times of the epic days of space exploration. It is in spanish but you can get google translate to turn it into any language nowadays. It is definitely worth the view and the read (about 8 mins). Follow this link: jordi.planas.cat/2008/11/mis-especiales-aventuras-espaciales.html

In the next posts, we will review the adventures of the other breakfast pal, inventor and world explorer +Joan Batet crossing the Sahara desert by car and how he realized that the metals of the car were distorting the magnetic compass. Back in those days, without GPS, the magnetic perturbation of a metal could mean live or death.


Thanks for visiting Magnets Solve Problems,

Xavi

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Don't crack under pressure Many materials respond to stress by rearranging their atoms in an abrupt way called detwinning. Here we prepared an animation of this process based on a computer simulation.

What is actually happening? This material is made of rectangular patches in which one side is slightly longer than the other. This can happen in, for instance, the so-called tetragonal or orthorhombic structures. Not everything in this life is like salt which is perfectly cubic and all sides of its patches (known as unit cells) have the same dimensions.

On these grounds, if you compress such materials from one side, as shown in the animation (notice the arrow briefly appearing at force panel), and you do not let them move further to the left.. then the material will decide to swap its long and short edges in a an abrupt process. In the intermediate steps there will be a mixture of patches pointing along different directions, that is a twinned state of the affairs. But if the pressure continues to act further (or the inertia of a force applied not too long ago), then the material will end up adjusting to the new arrangement in which short and long edges have been swapped.

This is, to some extend, a way how to write information in some piezo/ferroelastic materials. We will discuss it a little bit more in the next posts. Also, some of you may be asking why there is a panel with title magnetic field. We will go to this as well in the next posts but let me advance that magnetic field can also be a way how to induce pressure in a contact-less manner. Sounds magic but it works.

Thanks for reading,

Xavi


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Sharp edges get hot When it comes to electricity, sharp edges are a hot spot. As we mentioned in the previous posts, magnetism and electricity have become very good friends because electric currents can now be used to rotate magnets! (Well.. to be precise, it is the magnetization what is actually rotating in devices). This feature has let change from writing on magnets using magnets to a novel writing on magnets using electricity. Magnets are still the most wonderful storage media so it is a good idea to write on them. However, as a writing instrument, magnets are pretty bad pencils: they are thick and mess the information around and far from them. Therefore, the fashion became now to write on magnets using electric pulses.

In the animation below, we show a piece of magnetic media with the shape of a cross. The central part of the cell shown below can contain one bit of information which can be written by launching electrical pulses along selected pairs of the cross edges (called terminals). However, due to the sharp edges present in this design, the electricity agglomerates at the edges (see red areas glowing) and so writing becomes much stronger on those areas than in the central region. To solve that one has to develop new geometries that prevent this and/or make sure that just by writing on one of the corners that will be properly recognized as a "0" or a "1". We are working on that right now.

Stay tuned and thanks for reading!

.. and do not forget to subscribe to this page if you liked this post.

Xavi Marti


Further reading

First time we wrote at ambient temperature on an antiferromagnet using magnets
Room-temperature antiferromagnetic memory resistor
http://rdcu.be/oPPS
contributed also by +Carlos Frontera and +Ignasi Fina Martínez

Recent review on how we can now write on antiferromagnets using electricity
Antiferromagnetic spintronics
dx.doi.org/10.1038/nnano.2016.18
Electric control of antiferromagnets
ieeexplore.ieee.org/document/7562530
also written together with +Ignasi Fina Martínez


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Always positive No matter how you hit a piece of antiferromagnetic material using electrical discharges, there will be one way to create an incremental step of +1 that will be stored into that rock like if you scratched one more line. We have been witnessing a furious research recently on how a brick of these so-called antiferromagnetic material can be used to count electrical pulses that could come from a variety of origins: you could count visitors coming in and out of a mall, cars in the streets, occupied seats in an airplane, etc.

Let us describe what the attached animation is about. First, we sketched one piece of antiferromagnetic material which we shaped as a cross (top left) using lithography. The illustration shows arrows representing the electrical current (shorter or longer depending on the current intensity) flowing between two of those terminals. Likewise, we printed colored lines that circle the areas with larger current. The bottom plot displays the set of electric current patterns that we are sending thru the device and, finally, on the far right we show a two-dimensional map of the magnetic properties of the area near the center of the cross.

Each current pulses seems to push from dark to a more white contrast the latter map. This is because the overall color of the picture encodes/stores the amount of electrical pulses received. Why is it so? The map represents the amount of antiferromagnetic material which is pointing along or perpendicular to the current. The current flow itself naturally acts as a torque wrench rotating such magnetic properties from "parallel to" into "perpendicular to" the current flow. This is the result of the spin-orbit torques in antiferromagnets recently predicted by our co-contributor Jakub Zelezny in a Letter sent to Physical Review Letters (doi.org/10.1103/PhysRevB.95.014403). As you have noticed, we start in a fully-dark image which we previously prepared by sending pulses using a specific arrangement of the four terminals in the device we will discuss in the next post. By just using two terminals we can record all the current pulses passing by, each one of them producing a small incremental step. By calibrating the red curve shown as an inset, one can infer how many pulses were sent.

In the next post, we will describe with +Ignasi Fina Martínez how we can produce such pulses using piezoelectric impulses and a spare battery so that we can count vehicles.

Stay tuned, for more, thanks for reading,

Xavi Marti


If you want to know more, you can have a look at the recent broad audience text posted by +Ignasi Fina Martínez and myself at ieeexplore.ieee.org/document/7562530 as requested by conference organizers after the positive reception of our seminar this summer at Stanford.

Today just came out a nice review of all the talks at the latest Spice Workshop on antiferromagnetic materials, you can see a pre-print of it at arxiv.org/pdf/1701.06556v1.pdf, or just watch all YouTube talks at this address: www.spice.uni-mainz.de/afm-workshop-2016-talks
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