Magnetic complexity in RScT (R=Gd, Pr, T=Sb, Ge) based compound*

Ternary RTX intermetallics, where R = rare earth, T = transition metal, X = p-block element, are structurally and magnetically diverse and are among the most interesting intermetallic compounds to explore (Gupta et. al. JALCOM 618 (2015) 562). For example, GdScGe crystallizes in tetragonal CeScSi-type structure and undergoes paramagnetic to ferromagnetic (FM) transition at T_C = 350K, while PrScGe (same CeScSi-structure type) has an antiferromagnetic (AFM) transition at T_N = 140K followed by a second AFM transition at T_N = 88K and then FM transition at T_C = 80K. When germanium is replaced by antimony, the GdScSb compound crystallizes in a closely related tetragonal CeFeSi-type and orders AFM at T_N ~55K. Here we present a systematic study of the interplay between crystal structure and magnetism in Gd_1-xPr_xScGe and GdSc(Ge_1-xSb_x). The substitution of heavy lanthanide, Gd, with light lanthanide, Pr, results in a complex magnetic ground state with a large exchange bias of H_E ~ 1.06 kOe at T = 2K.