Spin-Reorientation Dynamics and Strong-Spin Phonon Coupling in Ce-substituted SmCrO$_3$

TL;DR

This study investigates how substituting Ce$^{3+}$ in SmCrO$_3$ affects its magnetic structures, spin-phonon coupling, and potential for spintronic applications, revealing significant changes in magnetic and lattice dynamics.

Contribution

It demonstrates that site-specific Ce$^{3+}$ substitution modulates magnetic phases, enhances spin-phonon coupling, and influences lattice distortions in SmCrO$_3$ perovskites, a novel insight for material optimization.

Findings

Ce$^{3+}$ substitution transforms magnetic states from weak ferromagnetic to antiferromagnetic.

Enhanced coercive field and exchange bias observed in Ce-substituted samples.

Significant spin-phonon coupling linked to structural distortions in Ce-doped SmCrO$_3$.

Abstract

We report the influence of Ce$^{3+}$ substitution on the magnetic structures and phonon dynamics in SmCrO$_3$ perovskites. Magnetic landscapes are spanned by long-range canted anti-ferromagnetism, AFM with Neel temperatures $\sim$196 K accompanied by spin-reorientation transitions, T$_{SRPT}$ at 42 K. In Sm$_{0.9}$Ce$_{0.1}$CrO$_3$ (SCCO), Ce$^{3+}$ substitution at Sm$^{3+}$ sites transform the weak ferromagnetic (FM) $\Gamma_4$ state into robust AFM $\Gamma_1$ configuration through a gradual crossover. Such coexistence of magnetic spin configurations $\Gamma_1$(AFM) to $\Gamma_4$ (WFM) results in the enhanced high coercive field and a pronounced exchange bias-field, $H_{\mathrm{EB}}$ $\sim$ 2 kOe. Spin-only driven magneto-crystalline anisotropy of Cr$^{3+}$ and spin-orbit driven magnetic moment in Sm$^{3+}$, and Ce$^{3+}$ exhibits spin-phonon coupling through $A_{1g}(6)$ 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 higher structural distortion in SCCO. These results demonstrate that site-specific R$^{3+}$ substitution modulates lattice distortions, spin-phonon coupling, and spin-orbit interactions, offering pathways to optimize perovskites for diverse spintronic applications.