Oscillatory magnetic anisotropy in Fe/Cr/Fe trilayers

Abstract

We report our experimental finding that there exists an oscillation of magnetic anisotropy with varying Cr sublayer thickness along the direction normal to the easy axis in Fe/Cr/Fe trilayers, where the easy axis is induced along a certain direction in the film plane by applying an external field during film deposition. Interestingly enough, the squareness of the hysteresis loop measured along the direction transverse to the easy axis exhibits an oscillatory behavior with a period of 5-6 Angstrom Cr sublayer thickness. We also witness that the magnetic anisotropy measured by a torque magnetometer shows an oscillating behavior with the same periodicity. Domain evolution pattern investigated using a time-resolved magneto-optical microscope reveals that domain configuration correspondingly oscillates between simple 180degrees type and complex non-180degrees type with varying Cr thickness. (C) 2004 American Institute of Physics.