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 Neel transitions, T$_N$ at $\sim$ 173 K, accompanied by spin-flip, T$_{ SF}$ at $\sim$ 10 K. Ce$^{ 3+}$ incorporation drives a modification of the spin-flip transition from the $\Gamma{ (G_x,A_y,F_z)}$ configuration to $\Gamma$ inducing a reorientation of the spin axis between the (001) 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, $\Delta$ S $\sim$ 45-40 J/kg-K for $\Delta$ 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.
Categories: cond-mat.mtrl-sci