Chiral domain wall motion in unit-cell thick perpendicularly magnetized Heusler films prepared by chemical templating

Abstract

Heusler alloys are a large family of compounds with complex and tunable magnetic properties, intimately connected to the atomic scale ordering of their constituent elements. We show that using a chemical templating technique of atomically ordered X′Z′ (X′ = Co; Z′ = Al, Ga, Ge, Sn) underlayers, we can achieve near bulk-like magnetic properties in tetragonally distorted Heusler films, even at room temperature. Excellent perpendicular magnetic anisotropy is found in ferrimagnetic X ₃Z (X = Mn; Z = Ge, Sn, Sb) films, just 1 or 2 unit-cells thick. Racetracks formed from these films sustain current-induced domain wall motion with velocities of more than 120 m s ⁻¹, at current densities up to six times lower than conventional ferromagnetic materials. We find evidence for a significant bulk chiral Dzyaloshinskii–Moriya exchange interaction, whose field strength can be systematically tuned by an order of magnitude. Our work is an important step towards practical applications of Heusler compounds for spintronic technologies.

Abstract

Heusler compounds are of great interest for spintronic applications. Here the authors report current driven domain wall motion in unit cell thick perpendicularly magnetized Heusler films with low current densities and show the velocity is dominated by the bulk chiral Dzyaloshinskii–Moriya exchange interaction.