Spectroscopic Kerr investigations of CoNi/Pt multilayers

Abstract

CoxNi1−x/Pt multilayers with x=0.4 and 0.5 were sputtered onto Si substrates. Magnetic and spectroscopic magneto-optic measurements (1.4–5.2 eV) reveal a Kerr rotation up to −0.48° at about 4.5 eV for a sample with rectangular hysteresis loop, about 170 kA/m coercivity, and a Curie temperature of about 300 °C. Pt layers could be made extremely thin (2.9 Å) without loss of perpendicular anisotropy and rectangular hysteresis loop. Simulations show that the Kerr rotation peak shifts back from 4.5 to 3.9 eV with increasing number of bilayers.