Magnetooptic properties of Fe∕Pd and Co∕Pd bilayers under hydrogen absorption

Abstract

Microstructure and magnetic properties of a Co/Pd multilayer on a controlled Pd/Si seed layer for double-layered perpendicular magnetic recording media J. Appl. Phys. 95, 8023 (2004); 10.1063/1.1736324 Magnetic and magneto-optical properties of Pd/Cr/Co multilayers

Hydrogen-mediated long-range magnetic ordering in Pd-rich alloy film

“…In our previous Pd/Fe, Co, Ni bilayer, and Pd/Co/Pd trilayer samples, the Kerr intensity is enhanced, similar to the previous report of Lederman et al 10,14 Lederman et al mentioned that the thicker Pd overlayers increase the MO enhancement, with remarkably large enhancement of 50% for a Fe (4.1 nm)/Pd (10.0 nm) sample. This effect results from a change in the optical properties of the Pd overlayer.…”

“…This effect results from a change in the optical properties of the Pd overlayer. 10 In contrast, the Kerr signal of the Co-Pd alloy film was reduced upon H 2 exposure, because Co-Pd alloy film is not a multilayer structure with a Pd overlayer. The reduction of Kerr signal actually implied the reduction of magnetic moment.…”

“…Many theoretical calculations have been performed and many experimental studies also point out that the hydrogenation of transition metals can change the magnetic susceptibility, magnetic interlayer coupling, and resistivity, which are mainly due to the change of electric structure. 10,11,24,25 In the Pd-rich alloy film, the magnetic moment is mainly located at the Co atoms, which are surrounded by the polarized Pd atoms. The indirect exchange interaction between Co moments is transferred through the conduction electrons in Pd medium.…”

“…[1][2][3][4] In our previous studies, the combination of Pd with magnetic transition metals provided an opportunity to modulate the magnetism, because Pd is an efficient catalyst in the dissociation of hydrogen molecules and the presence of Pd atoms can also help to stabilize hydrogen bounding to transition metals. [5][6][7][8][9][10][11][12] The palladium-hydrogen system has attracted intensive research efforts in physical chemistry as a model system because of its high storage capacity, its high sensitivity and selectivity to H 2 gas, and its ability to easily release hydrogen at room temperature. 13 Our previous reports on the effect of hydrogenation on Pd/Fe, Co, and Ni bilayers showed the significant enhancement of the magnetooptical Kerr signal, but without any observable modification of the intrinsic magnetic properties, such as the shape of the magnetic hysteresis loop and magnetic coercivity.…”

Substrate effect on the optical response of thin palladium films exposed to hydrogen gas

“…Recorded data, against time and against H 2 pressure, followed comparable behavior to reported changes in the resistivity of hydrogenated Pd films, although resistivity increases with hydrogen absorption [8]. This identifies the absorption of hydrogen into Pd as the dominant factor for the observed effect and confirms earlier measurements of the magnetooptical response of Fe/Pd bilayers upon hydrogen loading [19].…”