Magnetoresistance profiles of quasiperiodic Fe/Cr structures

We study theoretically the magnetoresistance properties of magnetic films (Fe/Cr) grown following the Fibonacci sequence. We use a theoretical Hamiltonian which includes Zeeman, cubic and uniaxial anisotropy, bilinear and biquadratic exchange energies. In particular, the presence of the uniaxial anisotropy in the Hamiltonian gives new symmetries to the system which were not discussed in previous works. Our physical parameters are based on experimental data recently reported, which contain biquadratic exchange coupling with magnitude comparable to the bilinear exchange coupling. We show the influence of the biquadratic exchange and anisotropies on the self-similar properties of the magnetoresistance profiles. (C) 2003 Elsevier Science B.V. All rights reserved.