Tunneling spectroscopy of the Heusler compound Co_2Cr_(0.6)Fe_(0.1)Al

摘要

The bias voltage and magnetization direction dependent differential conductivity dI/dV(V_(bias)) of tunneling junctions with the Heusler compound Co_2Cr_(0.6)Fe_(0.1) Al (CCFA) was investigated. The junctions contain A1O_x. 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 approx= ±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.