Disorder induced modification of Griffiths phase and observation of robust glassy magnetic behavior in multiferroic GaFeO3 compound

This article presents a comprehensive analysis of the magnetic properties of multiferroic GaFeO3 compound, to explore the Griffiths phase (GP) and robust glassy magnetic state. To investigate the origin of the GP and the robustness of glassy state, the intrinsic cationic disorder (or quenched disorder), which plays a pivotal role in appearing the exotic phenomena in this compound, has been tuned in a unique way of adjusting temperature cooling rates during the sample preparation. The bringing in disorder has been verified by performing full Rietveld refinement of the powder x-ray diffraction spectrum and analysing the extended x-ray absorption fine structure spectra. The enhancement in this disorder results in the emergence of the GP around the room temperature in those compounds, as confirmed by the conclusive experimental results and its theoretical fitting. The onset of the GP has been identified initially by the stair-like pattern in the inverse susceptibility curve. Subsequently, it has also been substantiated by the second harmonic ac susceptibility and meticulous zero-field magnetization measurements, viz., isothermal remanent magnetization and thermoremanent magnetization. However, on the contrary, in spite of having such enhancement in this intrinsic cationic disorder, no such significant change in the glassy magnetic behavior is observed for those compounds. Hence, in addition to the understanding of existing quenched disorder, the presence of magnetic inhomogeneity has also been substantiated from the critical analysis around the transition temperature. Eventually, how these effects give rise to the robust glassy magnetic phase and the GP that has been corroborated.