Spintronics

Both ferromagnetic and ferroelectric materials are widely used today, and can coexist together in so-called multiferroic compounds, which can be traced back to the 1950s. Their use in modern technology has seen a recent resurgence as multiferroic compounds are energy-efficient and could be used in information storage devices for computers, servers, and hard drives.

Working with researchers from Kyoto University in Japan, Northwestern Engineering’s James Rondinelli discovered the first all-inorganic halide perovskite-derived multiferroic material, exhibiting a form of ferroelectricity called hybrid improper ferroelectricity which is also coupled to magnetic properties. In the past, studies of multiferroic compounds had been largely limited to transition metal oxides, yet many other materials classes can exhibit this phenomenon.

Researchers from North Carolina State University, University of North Carolina at Chapel Hill, Massachusetts Institute of Technology (MIT),  National Renewable Energy Laboratory, Duke University, Wayne State University and The Hong Kong University of Science and Technology have created a mixed magnon state in an organic hybrid perovskite material by utilizing the Dzyaloshinskii-Moriya-Interaction (DMI). 

The resulting material has potential for processing and storing quantum computing information. The work also expands the number of potential materials that can be used to create hybrid magnonic systems.

Scientists from the University of Warsaw, Poland-based Military University of Technology, CNR Nanotec, the University of Southampton and the University of Iceland have designed a new photonic system with electrically tuned topological features, constructed of perovskites and liquid crystals. The new system can be used to create efficient light sources.

"We noticed that two-dimensional perovskites are very stable at room temperature, have high exciton binding energy and high quantum efficiency", said PhD student Karolina Lempicka-Mirek from the Faculty of Physics at the University of Warsaw, the first author of the publication. The team explained that these special properties can be used in the construction of efficient and unconventional light sources. 

A team of researchers from the National Renewable Energy Laboratory (NREL) and the University of Utah has developed a new type of LEDs that utilizes spintronics without needing a magnetic field, magnetic materials or cryogenic temperatures.

'The companies that make LEDs or TV and computer displays don't want to deal with magnetic fields and magnetic materials. It's heavy and expensive to do it,' said Valy Vardeny, distinguished professor of physics and astronomy at the University of Utah. 'Here, chiral molecules are self-assembled into standing arrays, like soldiers, that actively spin polarize the injected electrons, which subsequently lead to circularly polarized light emission. With no magnetic field, expensive ferromagnets and with no need for extremely low temperatures. Those are no-nos for the industry.'

An international researchers team recently found that a new 'double perovskite' material could become a more environmentally friendly platform for spintronics devices thanks to its lead-free nature. While the material in its current form is only magnetic below 30 K ' too low for practical applications ' developers at Linköping University in Sweden, together with colleagues in the US, the Czech Republic, Japan, Australia and China, say that their preliminary experiments are a promising step towards making rapid and energy-efficient information storage devices from this novel optoelectronic material.

Recently, researchers discovered that lead halide perovskites display interesting spin properties thanks to lead's strong spin-orbit coupling. This coupling links the motion of an electron to its quantum spin, and its strength determines how much the intrinsic spin of an electron will interact with the magnetic field induced as the electron moves through the material. Such a coupling is therefore important not only for the magnetic properties of a material, but also for the performance of any spintronics devices.

Researchers at Linköping University in Sweden have announced the development of an optoelectronic magnetic double perovskite. The discovery could open the door to combining spintronics with optoelectronics for rapid and energy-efficient information storage.

The team explains that one type of perovskite that contains halogens and lead has recently been shown to have interesting magnetic properties, opening the possibility of using it in spintronics. Spintronics is thought to have huge potential for the next generation of information technology, since information can be transmitted at higher speeds and with low energy consumption. However, magnetic properties of halide perovskites have until now been associated only with lead-containing perovskites, which has limited the development of the material for both health and environmental reasons.

In a recent report, Camilo X. Quintela and an international group in materials science, physics and engineering in the U.S., Norway, China and South Korea proposed a novel direction for materials design based on nitride antiperovskite and oxide perovskite crystals.

Schematic representation of the crystal structures of M3XN nitride antiperovskite and ABO3 oxide perovskite compounds and their interfaces. Image from Science Advances

In this work, they successfully layered perovskites and antiperovskites together, to create an interface with unique electrical properties for applications in a new class of quantum materials.

Scientists at the National Renewable Energy Laboratory and the University of Utah have shown that the transport of electrons with a particular spin state through a two-dimensional hybrid organic-inorganic perovskite can be manipulated by introducing special organic molecules in the multilayer structure. These are chiral, which means they prefer one electron helicity over the other. The new study may advance the field of spintronics'electronics that use the minuscule magnetic fields emanating from spinning electrons as well as the electric charges of the electrons themselves'for faster, smaller electronic devices that use less energy.

The Utah researchers worked together under the umbrella of the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier Research Center funded by the U.S. Department of Energy's Office of Science, Basic Energy Sciences.

Researchers from the University of Utah have developed two spintronics devices based on perovskite materials. The researchers used these new devices to demonstrate the high potential of perovksites for spintronics systems. This is a followup to the exciting results announced in 2017 by the same group that showed advantages of perovskites for spintronics.

The researchers used an organic-inorganic hybrid perovskite material with a heavy lead atom that features strong spin-orbit coupling and a long injected spin lifetime. The first device was a spintronic LED, which worked with a magnetic electrode instead of an electron-hole electrode. The perovskite LED lights up with circularly polarized electroluminescence.

Researchers at Cornell used theoretical techniques to predict that using intense mid-infrared laser light on a titanium perovskite can dynamically induce a magnetic phase transition ' taking the material from its ferromagnetic ground state to a hidden anti-ferromagnetic phase. This dramatic shift could have useful applications, particularly in optical information processing.

'It would be a kind of optical switch,' the researchers said. 'You have a material where it's magnetic and 'non-magnetic.' It's going between those two states with light'.