Structure and magnetic property of high-entropy intermetallics based on SmCo${}_5$ with the equiatomic ratios at Sm and co sites

SmCo${}_5$-based high-entropy intermetallic compounds (Sm${}_{1/3}$Pr${}_{1/3}$Nd${}_{1/3}$)(Co${}_{1/3}$Ni${}_{1/3}$Cu${}_{1/3}$)${}_5$ and (Sm${}_{1/4}$Ce${}_{1/4}$Pr${}_{1/4}$Nd${}_{1/4}$)(Co${}_{1/3}$Ni${}_{1/3}$Cu${}_{1/3}$)${}_5$ are prepared by substituting equiatomic ratios of rare earths at the Sm site and 3d transition metals at the Co site, respectively. Their crystal structures, chemical compositions, and magnetic properties are investigated. X-ray diffraction confirms that the two high-entropy intermetallic compounds are single phase with hexagonal CaCu${}_5$-type structure. The configuration entropies are 6.59R for (Sm${}_{1/3}$Pr${}_{1/3}$Nd${}_{1/3}$)(Co${}_{1/3}$Ni${}_{1/3}$Cu${}_{1/3}$)${}_5$ and 6.88R for (Sm${}_{1/4}$Ce${}_{1/4}$Pr${}_{1/4}$Nd${}_{1/4}$)(Co${}_{1/3}$Ni${}_{1/3}$Cu${}_{1/3}$)${}_5$, respectively. Both of them show spin-glass and field-induced ferromagnetic order due to the disordered ferromagnetic state induced by the site-disordered spin interactions at low temperature and the ordered arrangement of moments driven by the external field at the ferromagnetic transition temperature. Abnormal magnetic hysteresis loops are observed at the spin-glass order temperature, which is suggested to be associated with the anisotropy induced by the interaction coupling between the 4f rare earth and the 3d transition metal. (© 2021 Wiley‐VCH GmbH)