Evolution of Griffiths phase and spin reorientation in perovskite manganites

Abstract Magnetic properties of polycrystalline La1-xCaxMn0.9Cu0.1O3 (0.02 ≤ x ≤ 0.4) have been investigated in detail. All samples show a clear ferromagnetic-paramagnetic transition. The Curie temperature TC decreases with increasing Ca-dopant. Inverse susceptibility of all the samples deviates from Curie-Weiss law above TC, indicating the presence of a short range ferromagnetic and/or antiferromagnetic ordering state in the paramagnetic background. For 0.02 ≤ x ≤ 0.2, the upward deviation is attributed to antiferromagnetic interactions, while the downward for x ≥ 0.3 samples is caused by a Griffiths-like behavior, which is suppressed by an applied field. A charge ordering transition associated with an antiferromagnetic phase is detected in x ≥ 0.3 samples, the melting of which results in a spin reorientation transition and a new FM phase. Finally, the phase diagrams of this manganite system have been established.