Structural, electrical and magnetic phase evolution of Cr substituted GdMn1−xCrxO3 (0 ⩽ x ⩽ 0.2) manganites

Abstract

A series of GdMn1−xCrxO3 (0⩽x⩽0.2) have been synthesized by the conventional solid state reaction method mainly to understand the response of Cr substitution on structural, microstructural, magnetic and electrical transport properties. The X-ray diffraction shows that all samples crystallize with orthorhombic perovskite type symmetry with Pbnm space group. The room temperature Raman spectroscopy shows the reduction of Raman shift as doping concentration increase that related to anti-symmetric Jahn Teller stretching mode and symmetric-stretching mode. The temperature dependence of electrical resistivity show the semiconducting nature of these compounds and support the small polaron hoping model (SPH) and variable range hopping conduction model (VRH). The calculated hopping distance and activation energy increased as rate of Cr content increased whereas density of state at Fermi level decreased. The temperature dependence of magnetization presents that under the zero field cooling (ZFC) mode as doping concentration increases the net magnetization reverses its nature below irreversibility temperature. The magnetization results show that all samples show weak ferromagnetic nature that can further be improved with increasing Cr ions concentration.