Piezostrain modulation of magnetic damping in MBE-grown epitaxial Co₂FeAl/GaAs heterostructure

Abstract

The electric voltage manipulated magnetic dynamic properties of Co 2 FeAl/GaAs heterostructure bonded on PbZr 1−x Ti x O 3 piezoelectric substrate were investigated using the time-resolved magneto-optical Kerr effect technique at room temperature. The butterfly-like response of precession frequency dependence on the applied electric field was observed with no external magnetic field applied, indicating efficient manipulation of precession frequency solely by piezostrain. The magnetic damping of Co 2 FeAl was observed to be enhanced (decreased) under the strengthened compressive (tensile) strain modulation. The observed efficient tuning of both precession frequency and extrinsic damping constant at low magnetic fields is attributed to piezostrain modulated magnetic anisotropy value and its inhomogeneous distribution. When the magnetic dynamics is governed by the external magnetic field at highfield regime, electric field tunability of precession frequency and damping constant becomes weaker and the intrinsic damping constant shows no modulation. The electric voltage tuning of magnetic damping and the associated physical mechanism presented in this work can help designing strain-mediated low-energy cost spintronic devices.

Dual-axis control of magnetic anisotropy in a single crystal Co2MnSi thin film through piezo-voltage-induced strain

“…The magnitude of the additional uniaxial strain for a piezo-voltage of 80 V is approximately 5.2 × 10 −4 . 30 The magnetization vectors of the Co 2 MnSi samples ( S = 3 × 4 mm 2 ) were measured by longitudinal magneto-optical Kerr microscopy (Nano MOKE3) and a superconducting quantum interference device (SQUID) magnetometer. The piezo-voltages were applied with an Agilent B1500A with the leading and trailing time being both 100 ns.…”

“…The coexistence of the in-plane cubic and uniaxial magnetic anisotropies was observed when Heusler alloys are deposited on the GaAs (001) substrate. [28][29][30] The initial in-plane easiest axis (square loop) and easier axis (two-step loop) have been measured along two axes of minimum value of the cubic anisotropy, which is caused by the superposition of the uniaxial anisotropy. It is well known that a uniaxial stress could induce an extra uniaxial anisotropy in magnetic lms.…”