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

摘要

Voltage control of magnetic anisotropy (VCMA) in magnetic heterostructures isa key technology for achieving energy-efficiency electronic devices withultralow power consumption. Here, we report the first demonstration of the VCMAeffect in novel epitaxial Ru/Co2FeAl(CFA)/MgO heterostructures with interfacialperpendicular magnetic anisotropy (PMA). Perpendicularly magnetized tunneljunctions with the structure of Ru/CFA/MgO were fabricated and exhibited aneffective voltage control on switching fields for the CFA free layer. A largeVCMA coefficient of 108 (139) fJ/Vm for the CFA film was achieved at roomtemperature (4 K). The interfacial stability in the heterostructure wasconfirmed by repeating measurements. Temperature dependences of both theinterfacial PMA and the VCMA effect were also investigated. It is found thatthe temperature dependences follow power laws of the saturation magnetizationwith an exponent of ~2. The significant VCMA effect observed in this workindicates that the Ru/CFA/MgO heterostructure could be one of the promisingcandidates for spintronic devices with voltage control.