Geometrical control of the magnetization direction in high aspect-ratio PdNi ferromagnetic nano-electrodes

We present a study of electron-beam evaporated Pd0.4Ni0.6 alloy thin films by means of ferromagnetic resonance measurements on extended films of varying thickness and anisotropic magnetoresistance measurements of lithographically patterned high aspect-ratio ferromagnetic electrodes, respectively. The results reveal that the direction of the magnetization strongly depends on the electrode lateral dimensions, transitioning from in-plane magnetization for extended films to out-of-the-plane magnetization for electrode widths below 2-3 microns, reaching 58 degrees off-plane for 100 nm-wide nanoelectrodes.