Tunneling spectroscopy of the heusler compound Co2Cr0.6Fe0.1Al

The bias voltage and magnetization direction dependent differential conductivity dI/dV(V-bias) of tunneling junctions with the Heusler compound Co2Cr0.6Fe0.4Al (CCFA) was investigated. The junctions contain AlOx tunneling barriers and Co counter electrodes. A pronounced shoulder in the differential conductivity with parallel electrode magnetization and a sign change of the tunneling magnetoresistance at a bias voltage of similar or equal to +/- 500 mV were the most prominent features observed. The measurements are discussed in the framework of band structure related effects and inelastic excitations. X-ray absorption spectroscopy (XAS-TEY) investigations show that the CCFA/Al interface has an increased Fe content compared to the sputter target composition, presumably due to Fe buffer layer interdiffusion. (C) 2007 American Institute of Physics.