Spin reorientation induced exchange bias and dielectric relaxation behaviour in Sm-substituted YCrO₃

Abstract This study presents an unravelling of intricate magnetic behaviour involving spin reorientation (SR) and exchange bias (EB) along with dielectric relaxation behaviour in polycrystalline Y 1 − x Sm x CrO 3 (0 ⩽ x ⩽ 0.3) compounds. The x-ray diffraction spectra reveal the phase purity of the compounds, which are crystallized through distorted orthorhombic structures ( Pnma space group). Surface morphology confirms that the Sm doping decreases the average grain size from 0.43 to 0.35 µ m. The temperature-dependent magnetization elucidates SR phenomena from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">Γ</mml:mi> <mml:mn>4</mml:mn> </mml:msub> </mml:mrow> <mml:mrow> <mml:mtext> </mml:mtext> </mml:mrow> <mml:mrow> <mml:mo>(</mml:mo> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>A</mml:mi> <mml:mi>x</mml:mi> </mml:msub> </mml:mrow> <mml:mo>,</mml:mo> <mml:mrow> <mml:mtext> </mml:mtext> </mml:mrow> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>y</mml:mi> </mml:msub> </mml:mrow> <mml:mo>,</mml:mo> <mml:mrow> <mml:mtext> </mml:mtext> </mml:mrow> <mml:mrow> <mml:msub> <mml:mi>G</mml:mi> <mml:mi>z</mml:mi> </mml:msub> </mml:mrow> </mml:mrow> <mml:mo>)</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext> </mml:mtext> </mml:mrow> </mml:mrow> </mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">Γ</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> (C x , G y , F z ) magnetic spin configurations attributed to competing interactions between Sm and Cr below the SR transition temperature, T SR . Interestingly, below T SR , the EB field is observed to be approximately H EB ∼ 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 internal barrier-layer capacitor 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 in these compounds. These findings are essential for both practical applications and fundamental physics points of view.