Annealing dependence of magnetic properties in nanostructured Sm0.5Y0.5Co5

Abstract Nanocrystalline Sm 0.5 Y 0.5 Co 5 powders with high coercivity H C and enhanced remanence M r were prepared by mechanical milling and subsequent annealing. Annealing temperatures T ranging from 973 to 1173 K, and times t ranging from 1 to 5 min were used. X-ray diffraction (XRD) and DC-magnetization measurements were carried out to study the microstructure and magnetic properties of these samples. XRD patterns demonstrate that the average grain size 〈 D 〉 of the nanocrystalline powders depends on the annealing temperature T and time t : 〈 D 〉 ranges from 11 nm (for T =973 K and t =1 min) to 93 nm (for T =1173 K and t =5 min). Magnetic measurements performed at room temperature indicate high coercivity values ( H C >955 kA/m), and enhanced remanence ( M r / M max >0.5) for all samples. A strong annealing-induced grain size dependence of these magnetic properties was found.