A New Highly Anisotropic Rh-Based Heusler Compound for Magnetic Recording

Giant unilateral electric-field control of magnetic anisotropy in MgO/Rh2CoSb heterojunctions

A large voltage-controlled magnetic anisotropy (VCMA) effect is highly desirable for applications of voltage-torque magnetic random access memory. In this work, the dependence of magnetic anisotropy (MA) on the electric field in a MgO-based heterojunction consisting of a new Heusler alloy, Rh2CoSb, is studied using first-principles calculations. We find that the Rh-terminated MgO/Rh2CoSb heterojunction has a perpendicular MA and a giant VCMA coefficient of 7024 fJ V-1 m-1. Furthermore, the VCMA coefficient shows a characteristic of dependence on the electric-field direction. The origins of these behaviors are elucidated by orbital-resolved MA and second-order perturbation theoretical analysis. As the spin-down states of the in-plane orbital, dxy, are close to the Fermi level, the shift of these states induced by the electric field gives rise to significant changes of magnetic anisotropy energy, which is mainly responsible for the giant VCMA effect.

Topological Hall Effect Anisotropy in Kagome Bilayer Metal Fe_{3}Sn_{2}

Kagome lattice materials have attracted growing interest for their topological properties and flatbands in electronic structure. We present a comprehensive study on the anisotropy and out-of-plane electric transport in Fe_{3}Sn_{2}, a metal with bilayer of Fe kagome planes and with massive Dirac fermions that features high-temperature noncollinear magnetic structure and magnetic skyrmions. For the electrical current path along the c axis, in micron-size crystals, we found a large topological Hall effect over a wide temperature range down to spin-glass state. Twofold and fourfold angular magnetoresistance are observed for different magnetic phases, reflecting the competition of magnetic interactions and magnetic anisotropy in kagome lattice that preserve robust topological Hall effect for inter-kagome bilayer currents. This provides new insight into the anisotropy in Fe_{3}Sn_{2}, of interest in skyrmionic-bubble application-related micron-size devices.

Giant Thermoelectric Power Factor Anisotropy in PtSb1.4Sn0.6

We report on the giant anisotropy found in the thermoelectric power factor (S²σ) of marcasite structure-type PtSb_1.4Sn_0.6 single crystal. PtSb_1.4Sn_0.6, synthesized using an ambient pressure flux growth method upon mixing Sb and Sn on the same atomic site, is a new phase different from both PtSb₂ and PtSn₂, which crystallize in the cubic Pa3̅ pyrite and Fm3̅m fluorite unit cell symmetry, respectively. The large difference in S²σ for heat flow applied along different principal directions of the orthorhombic unit cell stems mostly from anisotropic Seebeck coefficients.

High-Throughput Design of Interfacial Perpendicular Magnetic Anisotropy at Heusler/MgO Heterostructures

The perpendicular magnetic anisotropy (PMA) at ferromagnet/insulator interfaces has important technological applications, such as in the fields of magnetic recording and sensing devices. The perpendicular magnetic tunnel junctions (p-MTJs) with strong PMA have recently attracted increasing interest because they offer high stability and device performance toward low energy consumption. Heusler alloys are a large family of compounds that offer promising magnetic properties for developing p-MTJs. However, it is challenging to select appropriate combinations of Heusler ferromagnets and insulators with the desired interfacial properties. Here, we report a systematic high-throughput screening approach to search for candidate Heusler/MgO material interfaces with strong PMA and other desired material properties for spintronic technologies. On the basis of the open quantum material repositories, we developed a series of material descriptors, including formation energy, convex hull distance, magnetic ordering, lattice misfit, magnetic anisotropy constant, cleavage energy, and tunnel magnetoresistance, to filter candidate Heusler/MgO interfaces among the possible 40 000 ternary Heusler compounds. After a comprehensive screening, five full-Heusler compounds, including Co₂CrAl, Co₂FeAl, Co₂HfSn, Fe₂IrGa, and Mn₂IrGe, and two half-Heusler compounds, PtCrSb and PtMnAs, were found to be promising for designing p-MTJs. This work demonstrates a new way for the high-throughput design of functional material interfaces for spintronic applications via exploiting the open quantum material repositories and developing effective material descriptors along with the large-scale ab initio calculations for material interfaces.