Controlling Electronics with Photoexcitation – Will Magnetite Launch Next-Generation Devices?

The Potential of Spintronics

Electronic components such as transistors are traditionally made of silicon and rely on semiconductors. The binary 0 and 1 signals indicate the flow or blocking of electric current. An alternative way to perform calculations is with spintronic devices, which operate on the spin of electrons (a fundamental quantum property) rather than on electric current (electron flow).

Spintronics has several advantages over classic electronic systemsespecially:

• Faster data because the spin can be changed much faster.
• Lower energy consumption because the spin can be changed using less power than is needed to maintain the flow of electrons needed to generate current.
• Instead of complex semiconductor materials, simple metals can be used.

Spintronics is mainly used in the production of hard drives and has enabled a significant increase in storage capacity over the last decade.

A material already used in spintronics is magnetitea naturally occurring mineral consisting of oxygen and two forms of iron with different oxidation states.

Despite the fact that the magnetic properties of magnetite have been known for decades, there is apparently still a lot to learn about it.

Scientists at EPFL in Switzerland have discovered that lasers can create new phase changes in magnetite that were previously unknown. This could lead to a new generation of electronics.

Hidden Properties of Magnetite

Scientists focused on magnetite because of its metal-insulator properties, which allow it to go from being a conductor of electricity to blocking it. This is also known as a phase transition, where the properties of a material suddenly change from one stage to another, a bit like how liquid water can turn into ice, with very different properties.

Using two different types of lasers, one emitting light at a wavelength of 800 nm and the other at 400 nm (infrared and visible light), the scientists discovered that new phases appeared in magnetite that had not been previously identified.

This is not a trivial matter, because the researchers had to detect changes occurring over an infinitesimal period of time. To do this, they used a technique called Ultrafast electron diffraction (UED), which allowed them to look at the motions of atoms lasting less than a picosecond, or a trillionth of a second.

Changing the spatial configuration

The usual atomic structure of magnetite is a “monoclinic lattice,” in which the unit cell is shaped like a slanted box with three unequal edges. Two of its angles are 90 degrees, and the third is different.

Light with a wavelength of 800 nm compresses the atomic structure of magnetite, turning it into a cubic structure. Ultrafast observation showed the researchers that this happened in a 3-step process.

In contrast, 400 nm caused the atomic structure of the metal to expand, creating a very stable configuration that made the metal a very stable insulator.

This configuration differs from the previously known stable equilibrium of magnetite and allows for a better understanding of what actually happens during the metal-to-insulator transition.

New electronic systems

This discovery means it is possible to change the effect of magnetite on spin and current using only laser light.

Thanks to very fast laser systems, it is possible to control the properties of a metallic material using photon pulses.

“Our research paves the way for a novel approach to controlling matter on ultrashort timescales using specially tailored photon pulses.

The ability to induce and control hidden phases in magnetite could have important implications for the development of advanced materials and devices.

For example, materials that can switch between different electronic states quickly and efficiently could be used in next-generation computers and memory devices.”

Better memory

Spintronics and magnetite are the new frontiers for electronics manufacturers. What began with the hard drive is now expanding to other memory systems.

For example, random access memory (DRAM) can be replaced by magnetic RAM (MRAM). The first version of this concept is already a commercialized product from Everspin and has been used in Airbus aircraft, thanks to its resistance to temperature changes as well as cosmic radiation compared to traditional memory systems.

Another advantage of MRAM is its smaller size and lower power consumption, which means up to 80% lower power requirements. This allows MRAM to be incorporated as cache memory into processors with larger total capacity, consuming less power and generating less heat, with both space and heat becoming key limiting factors in improving processors.

Photonics?

Applying a laser to changing magnetite conditions is reminiscent of the emerging field of photonics, one of the options we discussed in our article about companies that are moving computing beyond semiconductor systems.

A system that already uses lasers and light to perform calculations could benefit greatly from a memory system that relies on a phase change in magnetite induced by light. This could potentially enable direct conversion of the result of a calculation into data with little indirect power consumption and slowdown.

Spintronics companies

1. Everspin Technologies

Everspin is a division of Freescale (now NXP, ticker NXPI) that develops MRAM memory systems. It was spun off and listed on the stock exchange in 2016.

Everspin is considered a leader in MRAM technology, inheriting Freescale’s expertise in first to introduce MRAM chip to the market in 2006..

Because MRAM continues to function even after a power outage, it is increasingly used in mission-critical applications where critical data is important.

Driven by pervasive applications such as data analytics, cloud computing both terrestrial and extraterrestrial, artificial intelligence (AI) and edge AI, including industrial IoT, the persistent memory market is expected to grow at a CAGR of 27.5% during 2020-2030

Rotation

The company estimates the market will reach $7.4 billion by 2027. As of 2021, the company has no debt and positive free cash flow.

Everspin’s MRAM products currently occupy a small but growing niche, serving markets where reliability is critical, such as aerospace, satellites, data loggers, gaming, patient monitoring devices, etc.

Developments in chipsets, artificial intelligence and synaptic systems could also prove to be a long-term boost for the company.

2. NVE Corporation

Another leader in spintronics, NVE has been working on this technology since receiving the first MRAM patent in 1995..

Produces spintronic devices sensors AND insulatorsMainly used in measurement and sensing systems in automobiles, transmissions, medical equipment, power supplies and other industrial devices.

This puts NVE in a slightly different category than Everspin, with NVE being more of an industrial company with a strong position in a niche market (a magnetometer using spintronics), while Everspin is more of a memory/computing company, partnering and competing with the likes of Intel, Qualcomm, Toshiba, and Samsung, while also developing its own MRAM products.

This could make the stock more (or less) attractive, depending on the investor profile, with NVE stock likely to be more appealing to more conservative investors looking for a reliable dividend yield and security.