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

We investigate the effect of Ce3+ substitution on the magnetic ordering and phonon dynamics of the GdCrO3 orthorhombic perovskite. The Ce doped compound exhibits long-range canted antiferromagnetism with Néel transitions, TN at ~ 173 K, accompanied by spin-flip, TSF at ~ 10 K. Ce3+ incorporation drives a modification of the spin-flip transition from the ₄(Gₓ,Ay,Fz)configuration to ₄^ inducing a reorientation of the spin axis between the (00-1)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 Gd0.9Ce0.1CrO3 (GCCO) exhibits a remarkably large magnetic entropy change, -SM ~ 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 Cr3+ and spin–orbit–driven magnetic moments of Gd3+ and Ce3+ results in pronounced spin–phonon coupling, manifested through the A1g(6) vibrational mode. The observed temperature-dependent spectral evolution is consistent with behaviour reported in isostructural magnetic perovskites.