Effect of Sm on Structural, Magnetic and Dielectric Properties of YCr03 Perovskite

Abstract

This work synthesizes a series of Y1 -xSmxCrO3 (0 :S x :S 0.3) via a sol-gel auto­combustion route. The structural, magnetic and dielectric properties are characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), magnetization and permittivity measurements. The XRD spectra reveal the phase purity of compounds and are crystallized through distorted orthorhombic perovskite structures with the Pnma space group. Upon Sm substitution, lattice cell volume increases due to cationic size mismatch and XRD spectra shifting towards a lower Bragg angle. The average grain size is slightly elongated with Sm substitution confirmed through the FESEM image. X-ray Photoelectron Spectroscopy (XPS) has been employed to confirm the oxidation states of the compositional elements present in these compounds and further found the mix vacancy state of chromium ion (Cr3+ and Cr4+). Magnetic measurement shows intriguing properties, i.e. spin reorientation (SR) followed by zero field cooled exchange bias (ZEB) effect below TsR. This result is attributed to competing interaction between the Sm and Cr below TsR. Moreover, magnetic transition temperature (TN) is shifted towards higher temperatures from 140 K to 156 K. The temperature and frequency dependence of dielectric permittivity and loss tangent are analyzed over a wide temperature range of 90-523 K. The temperature-dependent dielectric permittivity (c) is decreased with Sm substitution. Moreover, all the compounds show relaxor-like ferroelectric behavior. The above intimate correlations among magnetic and dielectric properties can be helpful for practical application prospects in designing giant magnetoresistance and spin valve devices.