Magnetoelastic coupling in A₂FeReO₆ (A = Ba and Ca) probed by elastic constants and magnetostriction measurements Available to Purchase

Double perovskites A₂FeReO₆ (A = Ba, Ca) have been synthesized and studied using a combination of resonant ultrasound spectroscopy, magnetization, and magnetostriction measurements. A large softening in C₄₄ over a wide temperature range is observed for Ba₂FeReO₆ below its Curie temperature (T_C ≈ 311 K), which is indicative of a structural distortion. This softening is partially suppressed upon application of a low magnetic field. For Ca₂FeReO₆, both the longitudinal and shear moduli show a softening starting at T ≈ 160 K. In addition, magnetoelastic coupling constants have been estimated from elastic constants and magnetostriction data, which provide direct evidence of pronounced coupling between magnetism and the lattice degrees of freedom present in both compounds.