MAGNETIZATION REVERSAL IN COFE AG/FE/ZNSE THIN-LAYER SANDWICHES/

In recent work [J. Appl. Phys. 70, 10 (1991)] the spin valve effect (S VE) was measured in CoxFe1-x/Ag/Fe(x<0.7) thin layer sandwiches grown by molecular beam epitaxy. The field dependence of the SVE was correla ted with VSM magnetization data taken on the samples. It was found tha t only at low fields was there a correlation between the SVE resistanc e and the magnetization data. These results indicated a more complex r eversal mechanism that included substantial magnetizations in directio ns not measured in traditional VSM measurements. In order to more accu rately determine the field-dependent magnetization of the samples duri ng reversal, the longitudinal and transverse Kerr effects were measure d on the layers. The particular geometry used to measure the Kerr effe cts was for the light scattering plane to be perpendicular to the appl ied magnetic field. The transverse Kerr effect data, which in this geo metry are sensitive to the magnetization parallel to the applied magne tic field, replicated the VSM data. The longitudinal Kerr effect, whic h is sensitive to the net magnetization perpendicular to the applied f ield (in the plane of the film), indicated a substantial perpendicular magnetization component. Based upon previous work on epitaxial iron f ilMS,2-4 it appears that the magnetization reversal process proceeds b y transitions between easy axes. From these measurements, the anomalou s resistances observed as a function of the applied magnetic field in J. Appl. Phys. 70, 10 (1991), are explained by having one of the films soft, and two easy axes in the plane of the other film.