Influence of disorder on the appearance of Griffiths phases in La0.8−x□xCa0.2MnO3 (x=0.15 and 0.2) compounds

The La0.8−x□xCa0.2MnO3 (x=0.15 and 0.2) compounds were synthesized by the solid state reaction method. The X-ray diffraction (XRD) and magnetic measurements were used to study their physical and chemical properties. The structural characterization has revealed that these samples are crystallized in the orthorhombic structure with Pnma space group. Then, the magnetic properties of these compounds are discussed in detail, building on the magnetization and the susceptibility. The temperature dependence of magnetic susceptibility at higher temperature confirms the presence of the Griffiths phase above the Curie temperature which proves the existence of ferromagnetic clusters in the paramagnetic domain.