Griffiths phase and spontaneous exchange bias in La\(_{1.5}\)Sr\(_{0.5}\)CoMn\(_{0.5}\)Fe\(_{0.5}\)O\(_{6}\)

La\(_{1.5}\)Sr\(_{0.5}\)CoMn\(_{0.5}\)Fe\(_{0.5}\)O\(_{6}\) (LSCMFO) compound was prepared by solid state reaction and its structural, electronic and magnetic properties were investigated. The material forms in rhombohedral \(R\bar{3}c\) structure, and the presence of distinct magnetic interactions leads to the formation of a Griffiths phase above its FM transition temperature (150 K), possibly related to the nucleation of small short-ranged ferromagnetic clusters. At low temperatures, a spin glass-like phase emerges and the system exhibits both the conventional and the spontaneous exchange bias (EB) effects. These results resemble those reported for La\(_{1.5}\)Sr\(_{0.5}\)CoMnO\(_{6}\) but are discrepant to those found when Fe partially substitutes Co in La\(_{1.5}\)Sr\(_{0.5}\)(Co\(_{1-x}\)Fe\(_{x}\))MnO\(_{6}\), for which the EB effect is observed in a much broader temperature range. The unidirectional anisotropy observed for LSCMFO is discussed and compared with those of resembling double-perovskite compounds, being plausibly explained in terms of its structural and electronic properties.