Potential magnetic structure in Eu3InAs3revealed by magnetization and thermodynamic study.

We systematically investigate the magnetization and thermodynamic responses associated with the antiferromagnetic (AFM) transitions in magnetic semiconductor Eu₃InAs₃. The linear thermal expansion measurements reveal thataaxis expands whereasbandcaxes contract with the onset of the two AFM transitions atTN1andTN2. Using a simplified mean-field model incorporating AFM exchange interactions, easy-axis anisotropy, and Zeeman coupling, we analyze the potential magnetic structure change associated with the spin-flop and spin-flip transitions in field. The agreement between experimental and calculated magnetization data suggests that the1/3plateau alongbaxis results from a partial spin-flip transition in a multiple-easy-axis magnetic structure, where Eu₂-Eu₃and Eu₁sublattices order antiferromagnetically along thebandaaxes atTN1andTN2, respectively. Consistently, field dependence of magnetic entropy determined using low-Tadiabatic magnetocaloric effect indicates that the number of the ordered Eu²⁺moments atTN1is nearly twice that atTN2. Our results demonstrate that the magnetic structure in materials with strong spin-lattice coupling can be simply approached by a combined magnetization and thermodynamic study.