Hydrogen absorption induced reversible effect on magneto-optical property of Pd/Fe, Pd/Co and Pd/Ni bilayers

► Magneto-optical Kerr effect (MOKE) extinction angle was shifted by H2 exposure. ► Large enhancement of Kerr intensity was observed in Pd/Fe, Co and Ni bilayers. ► 104 Pa H2 was enough for the saturation of Kerr intensity enhancement. ► Reversibility of H2 absorption effect on MOKE was demonstrated.