Temperature dependence of magnetic switching and spin valve behaviors in MnAs/InAs/MnAs double heterostructure on GaAs(111)B

This study presents the first demonstration of temperature-dependent vertical spin valve (VSV) behavior in MnAs/InAs/MnAs double heterostructures (DH) grown on GaAs(111)B substrates by low-temperature molecular beam epitaxy (LT-MBE). Unlike conventional lateral spintronic devices, this vertical configuration enables precise control of the semiconductor channel thickness through epitaxial growth, offering significant advantages for device scalability and integration. Magnetization measurements reveal distinct, temperature-dependent magnetic switching characteristics of the top and bottom MnAs layers, a prerequisite for reliable VSV operation. Clear spin valve signals were observed in local magnetoresistance (MR) measurements, with switching fields and MR amplitudes strongly influenced by temperature variations. Notably, the amplitude of the spin valve signal increases with rising temperature due to improved impedance matching between ferromagnet and semiconductor, achieving a maximum spin injection efficiency of approximately 1.2% at 240 K. These findings not only verify the feasibility of MnAs/InAs/MnAs vertical structures for spintronic applications but also provide crucial insights into the temperature-dependent spin transport mechanisms in FM/SC hybrid systems.