Efficient Magnetization Direction Control of Magnetite for High-Density Spintronic Memory Devices

Scientists establish an energy-efficient method to reversibly alter ‘spin orientation’ or magnetization instructions in magnetite at space temperature level.

Over the last couple of years, standard electronic devices has actually been quickly reaching its technical limitations in computing and infotech, requiring ingenious gadgets that exceed the simple control of electron existing. In this regard, spintronics, the research study of gadgets that make use of the “spin” of electrons to carry out functions, is among the most popular locations in used physics. But, measuring, changing, and, in basic, dealing with this essential quantum home is no mean accomplishment.

Current spintronic gadgets — for instance, magnetic tunnel junctions — experience constraints such as high-power intake, low operating temperature levels, and extreme restraints in product choice. To this end, a group of researchers at Tokyo University of Science and the National Institute for Materials Science (NIMS), Japan, has actually released a research study in AIR CONDITIONER Nano, in which they provide a remarkably basic yet effective method to control the magnetization angle in magnetite (Fe₃O₄), a normal ferromagnetic product.

Figure 1. After using an external voltage, lithium ions circulation through the reduction-oxidation transistor and reach the bottom magnetite movie, changing its charge provider concentration and customizing the orientation of Fe spins. Credit: Tohru Higuchi, Tokyo University of Science

The group produced an all-solid reduction-oxidation (“redox”) transistor including a thin movie of Fe₃O₄ on magnesium oxide and a lithium silicate electrolyte doped with zirconium (Figure 1). The insertion of lithium ions in the strong electrolyte made it possible to accomplish rotation of the magnetization angle at space temperature level and substantially alter the electron provider density.

Associate Professor Tohru Higuchi from Tokyo University of Science, among the authors of this released paper, states “By applying a voltage to insert lithium ions in a solid electrolyte into a ferromagnet, we have developed a spintronic device that can rotate the magnetization with lower power consumption than that in magnetization rotation by spin current injection. This magnetization rotation is caused by the change of spin-orbit coupling due to electron injection into a ferromagnet.”

Figure 2. The modification in magnetization angle end up being visible under external voltages greater than 0.7 V, yielding a reversible modification of about 10°. At voltages greater than 1.2 V, the rotation is more noticable however ends up being irreparable due to long-term structural modifications in the magnetite stage. Credit: Tohru Higuchi, Tokyo University of Science

Unlike previous efforts that depend on utilizing strong external electromagnetic fields or injecting spin-tailored currents, the brand-new technique leverages a reversible electrochemical response. After using an external voltage, lithium ions move from the leading lithium cobalt oxide electrode and through the electrolyte prior to reaching the magnetic Fe₃O₄ layer. These ions then place themselves into the magnetite structure, forming Li_xFe₃O₄ and triggering a quantifiable rotation in its magnetization angle owing to a change in charge providers.

This impact enabled the researchers to reversibly alter the magnetization angle by roughly 10°. Although a much higher rotation of 56° was accomplished by upping the external voltage even more, they discovered that the magnetization angle might not be changed back completely (Figure 2). “We determined that this irreversible magnetization angle rotation was caused by a change in the crystalline structure of magnetite due to an excess of lithium ions,” describes Higuchi, “If we could suppress such irreversible structural changes, we could achieve a considerably larger magnetization rotation.”

The unique gadget established by the researchers represents a huge action in the control of magnetization for the advancement of spintronic gadgets. Moreover, the structure of the gadget is reasonably basic and simple to make. Dr. Takashi Tsuchiya, Principal Researcher at NIMS, the matching author of the research study states, “By managing the magnetization instructions at space temperature level due to the insertion of lithium ions into Fe₃O₄, we have actually made it possible to run with much lower power intake than the magnetization rotation by spin existing injection. The established aspect runs with a basic structure.”

Although more work stays to be done to maximize this brand-new gadget, the impending increase of spintronics will definitely open lots of unique and effective applications. “In the future, we will try to achieve a rotation of 180° in the magnetization angle,” states Dr. Kazuya Terabe, Principal Investigator at the International Center for Materials Nanoarchitectonics at NIMS and a co-author of the research study, “This would let us create high-density spintronic memory devices with large capacity and even neuromorphic devices that mimic biological neural systems.” Some other applications of spintronics remain in the extremely desirable field of quantum computing.

Only time will inform what this frontier innovation has in line for us!

Reference: “Room-Temperature Manipulation of Magnetization Angle, Achieved with an All-Solid-State Redox Device” by Wataru Namiki, Takashi Tsuchiya, Makoto Takayanagi, Tohru Higuchi and Kazuya Terabe, 2 November 2020, AIR CONDITIONER Nano.
DOI: 10.1021/acsnano.0c07906