Fabrication of MgAI_2O_4 Thin Films on Ferromagnetic Heusler Alloy Fe_2CrSi by Reactive Magnetron Sputtering

摘要

Epitaxial MgAI_2O_4 thin films were grown on Heusler alloy Fe_2CrSi by reactive magnetron sputtering of a MgAI_2 target in an O_2+Ar atmosphere. To grow MgAI_2O_4 on Fe_2CrSi, we inserted a protective layer of MgAI_2 between Fe_2CrSi and MgAI_2O_4 to prevent Fe_2CrSi from being oxidized. Growth of MgAI_2O_4 was found to be very sensitive to the MgAI_2 thickness and P_(o2) during deposition of MgAI_2O_4. A strong XRD peak of MgAI_2O_4 (004) was observed with an ultrathin (0.2 nm) MgAI_2 layer. The saturation magnetic moment of Fe_2CrSi was measured to be 370 emu/cm~3 (1.84_(μb) /f.u.) at room temperature and it is expected to have a high spin polarization. The Fe_2CrSi/MgAI_2O_4 heterostructure is promising for use in future spintronic devices.