Three-Terminal Hanle Signals in Schottky Tunnel Junctions with Co2FeAl0.5Si0.5 Full-Heusler Alloy Electrodes Deposited at Various Temperatures

We investigated the crystal structures, electrical transport properties, and three-terminal (3T) Hanle signals of Co2FeAl0.5Si0.5 (CFAS)/n-GaAs Schottky tunnel junctions fabricated with different deposition temperature of the CFAS (T-CFAS). CFAS thin films were deposited on the n-GaAs at T-CFAS ranging from room temperature to 300 degrees C, and 3T-Hanle signals were observed for all CFAS/n-GaAs junctions. Although the degree of structural ordering in the CFAS electrodes decreased and the rectifying characteristic disappeared as T-CFAS decreased, the spin resistance area products (Delta RA) increased and the estimated spin relaxation time (tau) decreased monotonically with decreasing T-CFAS. Moreover, the bias voltage dependence of Delta RA and tau became larger and smaller with decreasing T-CFAS, respectively. (C) 2013 The Japan Society of Applied Physics