Investigation of critical properties and magnetic disorder in La _0.7 Bi _0.3 MnO ₃ ceramic oxide

The present study emphasises the critical phenomena and characterisation of DC magnetisation and AC susceptibility measurements in La0.7Bi0.3MnO3 perovskite manganite. The compound has been synthesised using a conventional solid-state reaction method. Rietveld analysis of powder X-ray diffraction (PXRD) patterns shows that the compound exhibits rhombohedral crystal structure indexed to the R3¯c space group. The DC magnetisation versus temperature exhibits a high-temperature paramagnetic (PM) to low-temperature frustrated ferromagnetic (FM) transition. Using Bloch’s law, the existence of critical inhomogeneous FM agglomerates around blocking temperature (TK) has been confirmed. Further, the critical fluctuations at low temperatures have been understood using the Kouvel–Fisher (KF) method, which indicates the existence of the critical phenomena. By using the critical scaling analysis and KF method, the obtained values of β, γ and δ are comparable with the 3D Heisenberg-type spin interactions. The Langevin fit to the DC magnetisation versus magnetic field confirms the short-range interactions with inhomogeneities in the randomly dispersed magnetic spins. Hence, indicating temperature-dependent distortions in the magnetisation ordering. This type of investigation on critical phenomena and the results of La0.7Bi0.3MnO3discussed in this paper finds importance in devising advanced sensors useful for automotive and chemical catalytic degradation industries.