Magnetic Phase Diagrams of Y-Diluted Antiferromagnet Tb1-xYxB2C2 (0.2 ≤x ≤0.5)

Abstract

Magnetic B – T phase diagrams were examined by magnetization and specific heat experiments on the single crystalline Tb 1- x Y x B 2 C 2 (0.2 ≤ x ≤0.5) compounds, and neutron diffraction experiments was performed on the powder Tb 0.5 Y 0.5 11 B 2 C 2 sample. The magnetization curves evidence that the field-induced transition occurs from phase IV into phase II' through a mixed phase of both phases, where phase IV is antiferromagnetic and phase II' is a field-induced phase with the antiferromagnetic and antiferroquadrupolar order. The mixed phase (IV+II') is enhanced by the Y-dilution, and the lower and upper verges of the mixed phase become clearer in the differential magnetization d M /d B – B curves. The Y-dilution results in scaling down of the ordered phases regions in the B – T space. The ways of scale down of the ordered phase are different between two field directions along the tetragonal [100] and [110]-axes, that is, the anisotropy of phase stability is increased by the Y dilution. It is supposed ...