Growth and Transport Studies in M/I/$p$-SC Magnetic Tunnel Diodes Containing Different Tunnel Barrier Materials

Metal-insulator-semiconductor (MIS) magnetic tunnel diodes consisting of ferromagnetic metal (Fe) and semiconductor (Ga
_1-x
Mn
_x
As) electrodes with various tunnel barrier materials (AlAs, GaAs, ZnTe, and MgO) were fabricated. A clear tunneling magnetoresistance (TMR) effect was observed in all the samples. Magnetoresistance ratios at 2 K were observed to be 38% for AlAs, 11% for GaAs, 8% for ZnTe, and ~1% for MgO. Growth and transport studies strongly suggested that the small lattice mismatch between the barrier and the electrode materials and Mn-free interfaces are important for have significant influence on developing high-quality MIS magnetic tunnel diodes.