Structural, ferroelectric, and magnetic properties of room-temperature magnetodielectric GaFeO3

Polycrystalline GaFeO3 (GFO) samples were prepared through sol–gel method and sintered at 700 ∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ{\text{C}}$$\end{document}. The ceramics GFO crystallize in orthorhombic polar Pc21n symmetry as observed from FULLPROF profile fitting of XRD data. The Field Effect SEM results confirmed the average particle size ∼\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim$$\end{document} 25 nm with some porosity. Ferroelectric hysteresis loop reflecting a leaky nature was obtained at T < 350 K. The value of saturated polarization Ps, remnant polarization Pr, and coercive field Ec measured from P–E loop were 1.5 μC/cm2, 0.25 μC/cm2, and 0.50 kV/cm, respectively, at room temperature. In Raman spectrum analysis, no significant spin–phonon coupling indications near magnetic transition temperature were recorded. Temperature-dependent magnetic properties analyzed at zero field cooled and field cooled studies over temperature range of 350 K to 150 K infer that the material exhibited super-paramagnetic state at and above 297 K applicable in microwave devices, and magnetic Curie temperature value Tc increased from 220 to 315 K with decreasing particle size. Decrease in remnant magnetization Mr and increase in Ms/Mr value at room temperature were also observed in M–H hysteresis loop confirming the super-paramagnetic state of the material.