Increase in Spin Injection Efficiency of a CoFe/MgO (100) Tunnel Spin Injector with Thermal Annealing
Stanford University Stanford United States
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Postgrowth thermal annealing of a CoFeMgOs100 tunnel spin injector grown on aGaAsAlGaAs quantum well structure results in a significantly increased spin injection efficiency as inferred from the polarization of heavy-hole electroluminescence from a quantum well optical detector. The as-deposited sample displayed an initial polarization at 100 K of 43, which was increased to 52 after a 1 h anneal at 300 C, and finally to 55 after a second 1 h anneal at340 C. The polarization remained unchanged upon further annealing to temperatures as high as400 C. These results show that tunnel spin injectors based on CoFeMgO are robust with high thermal stability, making them useful for device applications.