Nanoscale Composition Control Applied on \({\boldsymbol {L}} 1_{\mathrm {\mathbf {0}}}\) FePtRh Film for Dot Patterning Using Magnetic Phase Change

A planar dot pattern was fabricated using the flat-patterning method involving nanoscale composition control. A small percentage of Fe and Pt atoms was locally diffused into an
L
1
\(_{\mathrm {0}}\)
FePtRh film by annealing, resulting in ferromagnetic dots with a diameter of 50 nm and a nonmagnetic spacing with a width of 100 nm. Nanoscale composition profiles around the dots were analyzed by an energy dispersive X-ray detector attached to a transmission electron microscope. Only the area in which the composition crossed the ferromagnetic-nonmagnetic threshold underwent a magnetic phase change. Magnetic force microscopy revealed ferromagnetic dots with a single-domain structure in the nonmagnetic matrix.