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

Polycrystalline GaFeO3 (GFO) samples were prepared through sol-gel method and sintered at 700 degrees C. The ceramics GFO crystallize in orthorhombic polar Pc2(1)n symmetry as observed from FULLPROF profile fitting of XRD data. The Field Effect SEM results confirmed the average particle size similar to 25 nm with some porosity. Ferroelectric hysteresis loop reflecting a leaky nature was obtained at T < 350 K. The value of saturated polarization P-s, remnant polarization Pr, and coercive field Ec measured from P-E loop were 1.5 mu C/cm(2), 0.25 mu C/cm(2), 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 T-c 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.