Magnetoresistance and magnetization of Fe/Cr(001) superlattices with noncollinear magnetic ordering

Abstract
We study the magnetization and magnetoresistance of superlattices with biquadratic exchange. The equilibrium states are analyzed on the base of the free energy expression that includes all terms up to the fourth order in components of magnetizations of magnetic sublattices. The correlation between the magnetization curve and the magnetoresistance for various orientation of magnetic field relative to the film plane is established. The experimental studies are made on the samples of molecular-beam epitaxy grown Fe/Cr superlattices. The positive magnetoresistance was found for the perpendicular-to-plane magnetic field. It is shown that this effect as well as the characteristic features of the magnetization curves are connected with the noncollinear magnetic alignment, which exists in our samples, and the fourth order magnetic anisotropy of unfamiliar type. © 1996 The American Physical Society.