Heusler-based synthetic antiferrimagnets

Abstract

Antiferromagnet spintronic devices eliminate or mitigate long-range dipolar fields, thereby promising ultrafast operation. For spin transport electronics, one of the most successful strategies is the creation of metallic synthetic antiferromagnets, which, to date, have largely been formed from transition metals and their alloys. Here, we show that synthetic antiferrimagnetic sandwiches can be formed using exchange coupling spacer layers composed of atomically ordered RuAl layers and ultrathin, perpendicularly magnetized, tetragonal ferrimagnetic Heusler layers. Chemically ordered RuAl layers can both be grown on top of a Heusler layer and allow for the growth of ordered Heusler layers deposited on top of it that are as thin as one unit cell. The RuAl spacer layer gives rise to a thickness-dependent oscillatory interlayer coupling with an oscillation period of ~1.1 nm. The observation of ultrathin ordered synthetic antiferrimagnets substantially expands the family of synthetic antiferromagnets and magnetic compounds for spintronic technologies.

Half‐Metallic Full‐Heusler and Half‐Heusler Compounds with Perpendicular Magnetic Anisotropy

“…It has been shown recently that using a novel chemical templating technique, the use of a chemical template underlayer formed from an atomically ordered CoAl layer allows for near-bulk-like magnetic properties in tetragonally distorted Heusler films grown on top of it, even for film deposition at room temperature, and that films only 1 or 2 unit cells thick display excellent PMA properties. [14,30] Table 2. Calculated cubic lattice constant of full-Heuslers that we have identified as not half-metals or near-half-metals in the regular structure, a r , and in the inverse structure, a i , total magnetic moment in the regular structure, m r , and in the inverse structure, m i , the difference between the total energy in the regular and inverse structures, E r -E i .…”

“…It has been shown recently that using a novel chemical templating technique, the use of a chemical template underlayer formed from an atomically ordered CoAl layer allows for near‐bulk‐like magnetic properties in tetragonally distorted Heusler films grown on top of it, even for film deposition at room temperature, and that films only 1 or 2 unit cells thick display excellent PMA properties. [ 14,30 ]…”

Epitaxial growth of magnetron sputtered NiAl on Ge mediated by native GeOx

“…Other materials that could benefit from an epitaxial seed are spinel-type compounds e.g. MgAl 2 O 4 [11,12] and Heusler alloys [13,14]. In fact, a pseudo spin-valve structure using a Heusler alloy has been made on a Si wafer buffered by epitaxial NiAl [15].…”

Measurement Geometry and Hydrostatic Pressure‐Dependent Magnetoresistance in All‐Oxide‐Based Synthetic Antiferromagnets

“…[ 7 ] SAFMs consist of alternating ferromagnetic layers and nonmagnetic spacers, where the adjacent ferromagnetic layers have antiparallel magnetizations due to the AF IEC. [ 6–16 ] When the magnetization configuration of adjacent ferromagnetic layers separated by an insulating spacer changes from antiparallel to parallel or vice versa, tunneling magnetoresistance (TMR), a key ingredient for magnetic sensors and memories, will develop. [ 16–24 ] The magnitude of TMR depends on the electronic structure of individual layers, scattering centers of insulating barriers, and/or interfacial electronic states.…”