Electron-Nonhomogeneous Magnetization Interaction in Thin Films of Cadmium Chromium Selenide.

The equations of motion for the electron spin and trajectory are solved in an inhomogeneous magnetic field, such as a magnetic domain wall or a periodic magnetic structure in a ferromagnetic semiconductor. It is found that the electron spin polarization is conserved only for electrons traveling through a magnetization reversal in a time shorter than the Larmor precession period of the spin around the magnetization vector. There are two different kinds of trajectories. For electron velocities and electric fields smaller than a critical value, the trajectory is cycloidal. When the critical value is exceeded the trajectory is modified drastically. It is concluded that these effects will be best observed in thin films of n-type CdCr2Se4, a high mobility ferromagnetic semiconductor. Thin CdCr2Se4 films were prepared by RF sputtering of stoichiometric mixtures of CdSe Cr2Se3 and subsequent annealing in Se atmosphere at elevated temperatures. Their electrical and magnetic properties are studied and discussed in view of the above calculations.