Spintronic RAM Gets A Little Closer To SRAM

January 7, 2020 by Al Williams 16 Comments

Sometimes it seems as though everything old is new again. The earliest computers used magnetic memory such as magnetic core. As practical as that was compared to making for example each bit of memory be a vacuum tube or relay flip flop, newer technology such as SRAM and DRAM displaced core and similar technologies. However, some of the newest technologies once again use magnetic fields. FRAM or ferroelectric RAM and magnetoresistive or MRAM both use magnetic fields to store data. Now Japanese researchers think they are on track to make MRAM more competitive with traditional RAM chips.

The Tokyo Institute of Technology researchers use new material combinations to make chips that store data based on the spin of electrons — the underlying reason for the way magnets behave. Their recent paper discusses USMR or Unidirectional spin Hall magnetoresistance and using this effect could greatly simplify the construction of MRAM cells.

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The Oldest Nuclear Reactor? Nature’s 2 Billion Year Old Experiment

January 7, 2020 by Al Williams 34 Comments

When was the first nuclear reactor created? You probably think it was Enrico Fermi’s CP-1 pile built under the bleachers at the University of Chicago in 1942. However, you’d be off by — oh — about 2 billion years.

The first reactors formed naturally about 2 billion years ago in what is now Gabon in West Africa. This required several things coming together: natural uranium deposits, just the right geology in the area, and a certain time in the life of the uranium. This happened 17 different times, and the average output of these natural reactors is estimated at about 100 kilowatts — a far cry from a modern human-created reactor that can reach hundreds or thousands of megawatts.

The reactors operated for about a million years before they spent their fuel. Nuclear waste? Yep, but it is safely contained underground and has been for 2 billion years.

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Tracking Vaccination History With Invisible Tattoos

January 3, 2020 by Sharon Lin 57 Comments

Nowadays, we still rely on medical records to tell when our last vaccinations were. For social workers in developing countries, it’s an incredibly difficult task especially if there isn’t a good standard in place for tracking vaccinations already.

A team at the Massachusetts Institute of Technology may be providing a solution – they’ve developed a safe ink to be embedded into the skin alongside the vaccine, only visible under a special light provided by a smartphone camera app. It’s an inconspicuous way to document the patient’s vaccination history directly into their skin and low-risk enough to massively simplify the process of maintaining medical records for vaccines.

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LC Oscillators, Animated

January 2, 2020 by Al Williams 23 Comments

We wish that all the beautiful animations that are available today to understand math and electronics had been around when we were in school. Nonetheless, they are there for today’s students and [Learn Engineering] has another gorgeous one covering LC oscillation. Check it out, below.

If you are thoroughly grounded — no pun intended — in LC circuits, you probably won’t learn anything new. However, the animations are worth watching, just to admire them, if nothing else.

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A New High-Performance Camera That Detects Single Photons

January 1, 2020 by Sharon Lin 15 Comments

There may soon be breakthroughs in the search for dark matter. A new publication in Optics Express reveals a camera consisting of superconducting nanowires capable of detecting single photons, a useful feature for detecting light at the furthest ends of the infrared band. The high-performance camera, developed by the National Institute of Standards and Technology (NIST), boasts some of the best performing photon counters in the world in terms of speed, efficiency, and color detection. The detectors also have some of the lowest dark count rates of any photon sensor, resisting false signals from noise.

The size of the detectors comes out to 1.6mm on each side, packed with 1024 sensors for high resolution imagery and fabricated from silicon wafers cut into chips. The nanowires are made from tungsten and silicon alloy with leads made from superconducting niobium.

In order to prevent the sensors from overheating, a readout architecture was used based on a previous demonstration on a smaller camera with 64 sensors adding data from rows and columns. The research has been in collaboration with the National Aeronautics and Space Administration (NASA), which seeks to include the camera in the Origins Space Telescope project.

The eventual goal is to use the arrays to analyze chemical compositions of planets outside of our solar system. By observing the absorption spectra of light passing through an exoplanet’s atmosphere, information can be gathered on the elements in the atmosphere. Currently, large-area single-photon counting detector arrays don’t exist for measuring the mid- to far-infrared signatures, the spectrum range for elements that may indicate signs of life. While fabrication success is high, the efficiency of the detectors remains quite low, although there are plans to extend the current project into an even bigger camera with millions of sensors.

In addition to searching for chemical life on other planets, future applications may include recording measurements to confirm the existence of dark matter.

[Thanks Qes for the tip!]

36C3: Build Your Own Quantum Computer At Home

December 30, 2019 by Sven Gregori 20 Comments

In any normal situation, if you’d read an article that about building your own quantum computer, a fully understandable and natural reaction would be to call it clickbaity poppycock. But an event like the Chaos Communication Congress is anything but a normal situation, and you never know who will show up and what background they will come from. A case in point: security veteran [Yann Allain] who is in fact building his own quantum computer in his garage.

Starting with an introduction to quantum computing itself, and what makes it so powerful also in the context of security, [Yann] continues to tell about his journey of building a quantum computer on his own. His goal was to build a stable computer he could “easily” create by himself in his garage, which will work at room temperature, using trapped ion technology. After a few iterations, he eventually created a prototype with KiCad that he cut into an empty ceramic chip carrier with a hobbyist CNC router, which will survive when placed in a vacuum chamber. While he is still working on a DIY laser system, he feels confident to be on the right track, and his estimate is that his prototype will achieve 10-15 qubits with a single ion trap, aiming to chain several ion traps later on.

As quantum computing is often depicted as cryptography’s doomsday device, it’s of course of concern that someone might just build one in their garage, but in order to improve future cryptographic systems, it also requires to fully understand — also on a practical level — quantum computing itself. Whether you want to replicate one yourself, at a rough cost of “below 15k Euro so far” is of course a different story, but who knows, maybe [Yann] might become the Josef Prusa of quantum computers one day.

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Magic-Angle Twisted Bilayer Graphene – Yes, That’s The Scientific Name

December 27, 2019 by Sharon Lin 14 Comments

In the world of physics research, graphene has been gaining popularity as one of the most remarkable materials in the last 15 years. While it may appear unassuming in common household goods such as pencil leads, the material boasts a higher strength than steel and a higher flexibility than paper. On top of all that, it is also ultra-light and an excellent conductor of electric current and heat.

Recently, physicists from the Massachusetts Institute of Technology discovered that stacking two sheets of graphene and twisting a small angle between them reveals an entire new field of material science – twistronics. In a paper published in Nature, researchers have taken a look into this new material, known as the magic-angle twisted bilayer graphene. By modifying the graphene’s temperature, they were able to cause the material to shift from behaving like an insulator to transforming into a superconductor.

A graphic in the New York Times demonstrates some of the interesting properties that arise from stacking and twisting two sheets. Scientists have long known that graphene is a one-layer-thick honeycombed pattern of carbon atoms, but actually separating a single sheet of graphene has been fairly difficult. A low-tech method pioneered by two physicists at the University of Manchester involves using sticky tape to pull apart graphene layers until a single layer is left.

Small imperfections that arise from slightly misaligned sheets manifests in a pattern that allows electrons to hop between atoms in regions where the lattice line up, but unable to flow in regions that are misaligned. The slower moving electrons are thus more likely to interact with each other, becoming “strongly correlated”.

The technique for measuring the properties of this new twisted graphene is similarly low-tech. After a single layer of graphene is separated by sticky tape, the tape is torn in half to reveal two halves with perfectly aligned lattices. One of the sides is rotated by about 1.3 degrees and pressed onto the other. Sometimes, the layers would snap back into alignment, but other times they would end up at 1.1 degrees and stop rotating.

When the layers were cooled to a fraction of a degree above absolute zero, they were observed to become a superconductor, an incredibly discovery for the physicists involved in the experiment. Further studies showed that different permutations of temperature, magnetic field, and electron density were also able to turn the graphene into a superconductor. On top of this, the graphene was also able to exhibit a form of magnetism arising from the movement of electrons rather than the intrinsic properties of the atoms. With so many possibilities still unexplored, it’s certain that twistronics will reveal some remarkable findings pretty soon.

[Thanks Adrian for the tip!]