Spin-Reorientation Dynamics and Strong Spin Phonon Coupling in Ce-Substituted SmCrO ₃

We report the influence of Ce3+ substitution on the magnetic structures and phonon dynamics in SmCrO3 perovskites. Magnetic landscapes are spanned by long-range canted antiferromagnetism, AFM with Néel temperatures, TN ∼196 K accompanied by spin-reorientation transitions, TSRPT at 42 K. In Sm0.9Ce0.1CrO3 (SCCO), Ce3+ substitution at Sm3+ sites transforms the weak ferromagnetic (FM) Γ4(Gx,Ay,Fz;FzR) state into the robust AFM Γ1(Ax,Gy,Cz;CzR) configuration through a gradual crossover. Such coexistence of magnetic spin configurations (Γ1(AFM) ⇋ Γ4(WFM)) results in the enhanced high coercive field and a pronounced exchange bias-field, HEB ∼2 kOe. Only-spin driven magneto-crystalline anisotropy of Cr3+ and spin–orbit driven magnetic moment in Sm3+, and Ce3+ exhibits spin-phonon coupling through A1g(6) mode in SCCO are consistent with the temperature dependent spectral features of the isostructural magnetic systems and quite significant in SCCO which is in accordance with the high structural distortion in SCCO. These results demonstrate that site-specific R3+ substitution modulates lattice distortions, spin–phonon coupling, and spin–orbit interactions, offering pathways to optimize perovskites for diverse spintronic applications.