Structural and magnetic properties of Ni 2MnIn Heusler thin films grown on modulation-doped InAs heterostructures with metamorphic buffer

Abstract

This paper reports on the morphological, structural, magnetic, and magneto-optic properties of Ni 2MnIn Heusler films grown on InAs-high electron-mobility transistor structures (HEMT) with metamorphic buffers for spintronic applications. Similar to our previous results on the Ni 2MnIn/InAs (001) system, the Heusler layer is found to have a (110) orientation relative to the (001) InAs-HEMT surface. We observe almost equal spin-polarizations for Heusler films on (001) InAs-HEMT as well as on (001) InAs. In addition, we find further support for interfacial intermixing previously reported for the Ni 2MnIn/InAs (001) system. On the other hand, the Heusler/InAs-HEMT system shows distinct morphologic, structural, and magnetic properties as compared to the Ni 2MnIn/InAs (001) system. In particular, more rapid and complex plastic deformation effects resulting in a high surface density of pin-holes in the Heusler films are found. We report on complex mutual deformation effects between the Heusler films and the underlying InAs-HEMT structure. Furthermore, a hysteresis loop squareness close to 1 for a 50 nm Heusler film on InAs-HEMT is observed. We tentatively associate these phenomena with the higher mismatch strain of the Ni 2MnIn/InAs-HEMT system compared to Ni 2MnIn films grown on (001) InAs.