Giant-magnetocaloric effect and phonon dynamics in (GdCe)CrO3

Abstract

Abstract We investigate the effect of Ce 3+ substitution on the magnetic ordering and phonon dynamics of the GdCrO 3 orthorhombic perovskite. The Ce doped compound exhibits long-range canted antiferromagnetism with Néel transitions, T N at ~ 173 K, accompanied by spin-flip, T SF at ~ 10 K. Ce 3+ incorporation drives a modification of the spin-flip transition from the $${\varGamma}_{4}\left({G}_{x},{A}_{y},{F}_{z}\right)$$ configuration to $${\varGamma}_{4}^{{\prime}}$$ inducing a reorientation of the spin axis between the $$\left(00\stackrel{-}{1}\right)$$ and (001) crystallographic planes. This spin reorientation is governed by Zeeman energy and produces pronounced field-induced irreversibility between FCC and FCW magnetization processes. The substituted compound Gd 0.9 Ce 0.1 CrO 3 (GCCO) exhibits a remarkably large magnetic entropy change, $$-\varDelta{S}_{M}$$ ~ 45 –40 J/kg-K for ∆H = 90 − 70 kOe at 3 K among the highest reported for rare-earth orthochromites. The interplay of spin-only magnetocrystalline anisotropy from Cr 3+ and spin–orbit–driven magnetic moments of Gd 3+ and Ce 3+ results in pronounced spin–phonon coupling, manifested through the A 1g (6) vibrational mode. The observed temperature-dependent spectral evolution is consistent with behaviour reported in isostructural magnetic perovskites.