Magnetism of metallic superlattices

Abstract

Artificially made layered materials such as modulated structures have added a new dimension to magnetism research. Important parameters are modulation amplitudes and wavelengths, concentration, interface matching, and orientation of the modulation. We have studied theoretically the electronic structure and magnetic properties of various coherent modulated structures by means of self-consistent spin-polarized LMTO band calculations using large supercells to describe the structure. For CuNi, modulations along [111] and [100] were studied for different assumed wavelengths and supercells. In all cases, the calculated Ni moments are found to be reduced compared to fcc Ni. Adjacent Cu layers acquire small moments of varying direction and strength, indicating that the Cu and the wavelength as well as the s-electron moments might be important to mediate the coupling between separated Ni layers. To study effects of local distortions, such as shear and stretching, the magnetic moment in bulk Ni and magnetic susceptibility in Pd have been calculated for tetragonally distorted lattices.