Structure, magnetic properties, and thermal stability of Sm1−x Tm x Co5 compounds

Abstract

Structure, magnetic properties, and thermal stability of ternary Sm1−x Tm x Co5 compounds were studied via X-ray diffraction (XRD), thermal magnetic analysis (TMA), and magnetic measurements. XRD results show that all the compounds have a main phase of hexagonal CaCu5-type crystal structure with small amount of impurity phases; increasing Tm content is associated with contraction of the hexagonal unit cell in the direction of the c axis and expansion of the a and b parameters. TMA results indicate that the Curie temperature (T C) of Sm1−x Tm x Co5 compounds gets higher with the increase in Tm content. Magnetic measurements show that both the magnetic anisotropy field (H A) and the magnetization at an applied field of 7 T (M 7 T) decrease with the increase of Tm content. However, the thermal stability of both the H A and M 7 T of all the Tm doped compounds is remarkably improved compared with that of the pure SmCo5 compound, leading to the result that both the M 7 T and H A of Sm0.8Tm0.2Co5.2 are higher than those of SmCo5 compound at 473 K, which indicates the good potential of Tm doped compound in the practical applications at elevated temperature.