Change of interlayer exchange coupling in Fe/Y multilayers by hydrogenation

We have investigated the change of interlayer exchange coupling in Fe (3.0nm)/Y (t nm) multilayers upon increasing the thickness of the spacer layer by hydrogenation. The coupling behavior changes from an antiferromagnetic (AFM) state to a non-coupled (NC) state, both before and after hydrogenation. The maximum value of coupling strength (J₁) is found to become much lower after hydrogenation than before hydrogenation. The range of the spacer layer thickness for maintaining AFM coupling is found to be extended from 1.4 nm to 1.8 nm by hydrogenation. Both the difference in the AFM coupling strength and the extension of the spacer layer thickness of AFM coupling should be attributed to the change from a Y layer to a yttrium-hydride (Y-H) layer by hydrogenation.