Abstract
The magnetic proximity effect (MPE), ferromagnetic (FM) coupling at the interface of magnetically dissimilar layers, has attracted much attention as a promising pathway for introducing ferromagnetism into a high-mobility nonmagnetic (NM) conducting channel. Recently, our group found giant proximity magnetoresistance (PMR), which is caused by MPE at an interface between a NM semiconductor InAs quantum well (QW) layer and a FM semiconductor (Ga,Fe)Sb layer. The MPE in the NM semiconductor can be modulated by applying a gate voltage and controlling the penetration of the electron wave function in the InAs QW into the neighboring insulating FM (Ga,Fe)Sb layer. However, optimal conditions to obtain strong MPE at the InAs/(Ga,Fe)Sb interface have not been clarified. In this paper, we systematically investigate the PMR properties of (, 5, 7.5, and 10%)/(Ga,Fe)Sb bilayer semiconductor heterostructures under a wide range of gate voltage. The inclusion of Ga alters the electronic structures of the InAs thin film, changing the effective mass and the QW potential of electron carriers. Our experimental results and theoretical analysis of the PMR in these (Ga,Fe)Sb heterostructures show that the MPE depends not only on the degree of penetration of the electron wave function into (Ga,Fe)Sb but also on the electron density. These findings help us to unveil the microscopic mechanism of MPE in semiconductor-based NM/FM heterojunctions.
- Received 15 December 2021
- Revised 10 May 2022
- Accepted 11 May 2022
DOI:https://doi.org/10.1103/PhysRevB.105.235202
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