The magnetoelectric effect in transition metal oxides: Insights and the rational design of new materials from first principles

Abstract

The search for materials displaying a large magnetoelectric effect has occupied researchers for many decades. The rewards could include not only advanced electronics technologies, but also fundamental insights concerning the dielectric and magnetic properties of condensed matter. In this article, we focus on the magnetoelectric effect in transition metal oxides and review the manner in which first-principles calculations have helped guide the search for (and increasingly, predicted) new materials and shed light on the microscopic mechanisms responsible for magnetoelectric phenomena.

Magnetic field cycling effect on the non-linear current-voltage characteristics and magnetic field induced negative differential resistance in α-Fe1.64Ga0.36O3 oxide

“…[1][2][3][4][5] The hematite system stabilizes in rhombohedral structure with space group R3C. The spins of Fe 3+ ions in each rhombohedral planes (say, two alternating planes A and B) from ferromagnetic (FM) order, but spins of Fe 3+ ions between A and B planes are coupled by antiferromagnetic (AFM) superexchange interactions (Fe 3+ A -O 2− -Fe 3+ B ).…”

“…The coupling between electronic charge and spin is essential for the spintronics applications of magnetic semiconductors. 2,12 The current-voltage (I-V) curve correlates the charge flow through a ferromagnetic semiconductor under test (FMSUT) with applied voltages and it is an important tool to determine suitability of the material in electronic devices. The I-V characteristics can be used to estimate electrical conductivity, charge accumulation and charge injection efficiency at the interfaces of FMSUT and electrodes.…”

Novel magneto-electric multiferroics from first-principles calculations

“…In the P nma phase, the symmetry allows for a small canting of the otherwise anti-ferromagnetically ordered spins, yielding weak ferromagnetism [86]. A center of inversion is preserved however in which case weak ferromagnetism is incompatible with a linear magneto-electric effect [87]. Inducing ferroelectricity by strain breaks the inversion symmetry and additionally offers the possibility of achieving a linear magneto-electric coupling.…”

“…This section will provide only a brief overview of the second strategy, which relies on subtle alterations of chemistry, bonding, structure and electronics at the interface, and hence where first-principles calculations have proved invaluable. For more comprehensive reviews, we refer the reader to references [148,149,150,151,87].…”

Dynamical systems study in single-phase multiferroic materials

“…Such materials in single-phase were usually thought to be rare [13], and hence multiferroic composites in 2-phase, i.e., a ferroelectric layer strain-coupled to a ferromagnet, are usually deemed to be the replacement [5,[14][15][16][17][18][19][20]. However, there have been recent resurgence of interests [21,22] and some mechanisms of coupling polarization and magnetization in single-phase materials are coming along [23][24][25]. This can lead to possible technological applications [26] of switching a bit of information (stored in the magnetization direction) by an electric field [27].…”