Spin Reorientation Induced Exchange Bias and Dielectric Relaxation Behaviour in Sm-substituted YCrO3

Abstract

This study presents an unravelling intricate magnetic behaviour involving spin reorientation (SR) and exchange bias (EB) along with dielectric relaxation behaviour in polycrystalline Y1-xSmxCrO3 (0 ≤ x ≤ 0.3) compounds. The X-ray diffraction spectra reveal the phase purity of compounds, which are crystallized through distorted orthorhombic structures (Pnma space group). Surface morphology confirms that Sm doping decreases average grain size from 0.43 to 0.35 µm. The temperature-dependent magnetization elucidates SR phenomena from Γ_4 (A_x,F_y,G_z) to Γ_2 (Cx, Gy, Fz) magnetic spin configuration attributed to competing interaction between the Sm and Cr below spin reorientation transition temperature, TSR. as shown in Fig.1. Interestingly, below TSR, the EB field is observed to be approximately HEB ~ 0.8 T (at 5 K) for the x = 0.3 composition that is attributed to the strong coupling of Sm and Cr sublattices. Temperature-dependent dielectric measurements indicate two thermally activated relaxations with Sm substitution. The high-temperature relaxation stems from IBLC effects at grain boundaries, while the low-temperature relaxation arises from dipolar effects due to charge carrier hopping within grains. Moreover, these compounds exhibit p-type conduction, driven by hole hopping between neighbouring sites. This work emphasizes the crucial role of Sm and Cr coupling in shaping the fascinating and complex phenomena of SR and EB of the compounds. These findings are essential for both practical application and fundamental physics point of view.