Voltage control of magnetic anisotropy in epitaxial Ru/Co2FeAl/MgO heterostructures

TL;DR

This study demonstrates voltage-controlled magnetic anisotropy in epitaxial Ru/Co2FeAl/MgO heterostructures, showing large VCMA coefficients and stability, promising for energy-efficient spintronic devices.

Contribution

First demonstration of VCMA effect in epitaxial Ru/Co2FeAl/MgO heterostructures with interfacial PMA and high VCMA coefficients at room temperature and 4 K.

Findings

Achieved large VCMA coefficient of 108-139 fJ/Vm.

Confirmed interfacial stability through repeated measurements.

Investigated temperature dependence following power laws of saturation magnetization.

Abstract

Voltage control of magnetic anisotropy (VCMA) in magnetic heterostructures is a key technology for achieving energy-efficiency electronic devices with ultralow power consumption. Here, we report the first demonstration of the VCMA effect in novel epitaxial Ru/Co2FeAl(CFA)/MgO heterostructures with interfacial perpendicular magnetic anisotropy (PMA). Perpendicularly magnetized tunnel junctions with the structure of Ru/CFA/MgO were fabricated and exhibited an effective voltage control on switching fields for the CFA free layer. A large VCMA coefficient of 108 (139) fJ/Vm for the CFA film was achieved at room temperature (4 K). The interfacial stability in the heterostructure was confirmed by repeating measurements. Temperature dependences of both the interfacial PMA and the VCMA effect were also investigated. It is found that the temperature dependences follow power laws of the saturation magnetization with an exponent of ~2. The significant VCMA effect observed in this work indicates that the Ru/CFA/MgO heterostructure could be one of the promising candidates for spintronic devices with voltage control.