Single crystal growth, magnetic anisotropy, specific heat, and high-field magnetization in RInCu₄, R = Gd, Tb

RInCu₄ is a magnet with geometric frustration, where R (lanthanoid atoms) forms the face-centered cubic (FCC) sublattice. Among this group of compounds, GdInCu₄ and HoInCu₄ show partial disorder (PD) below antiferromagnetic transition temperatures, unlike the typical magnetic structures in FCC sublattice magnets. On the other hand, other RInCu₄ members' magnetic structures remain unrevealed. This study investigates GdInCu₄ and TbInCu₄ single crystals' magnetic susceptibility, specific heat, and high-field magnetization measurements to gain insights into their magnetic structures. Results suggest that GdInCu₄ exhibits an additional PD phase at lower temperatures alongside the previously proposed PD phase. The magnetic structures within these phases are single-Q structures. Conversely, TbInCu₄ shows possible multiple-Q antiferromagnetic structures and successive field-induced magnetic transitions. These differences in magnetic structures stem from the local anisotropy of the 4f moments. (author)