Structural and magnetic phase transitions along with optical properties in GdMn1-xFexO3 perovskite

Abstract

Herein, we report the structural evolution and the rich sequence of magnetic transitions in GdMn1–xFexO3 (x = 0, 0.3, and 0.5) synthesized through the sol-gel technique. Rietveld refinement of X-ray diffraction patterns reveals a structural transformation from O′ to O type orthorhombic one accompanied with a decrease in lattice volume when x increases from 0 to 0.5. The decrease in lattice volume is due to the presence of Mn4+ confirmed from X-ray photoelectron spectroscopy and photoluminescence (PL) studies. Such a structural transformation considerably reduces the Jahn-Teller distortion factor as indicated by Raman and PL spectra. The temperature dependent magnetization shows an increase in Néel temperature (TN) from ∼42 K for pristine GdMnO3 to almost room temperature for x = 0.5. Interestingly, we observe a spin reorientation temperature (TSR) at ∼270 and ∼253 K for x = 0.3 and 0.5, respectively. The mixed valency of Mn, i.e., Mn3+ and Mn4+ not only demonstrates a spin-glass (SG) behavior but also contributes toward the strong emission spectra irrespective of Fe concentration. The structural and magnetic properties of GdMnO3 after doping Fe suggest a possible way to achieve a better magnetoelectric coupling and modify the multiferroic property.