Magnetic phase inhomogeneity in frustrated intermetallic compound Sm2Ni0.87Si2.87

A new ternary compound Sm2Ni0.87Si2.87, belonging to intermetallic R2TX3 family (R = rare-earth, T = transition metals, X = Si, Ge, etc.), could be synthesized in single phase only by the deliberate introduction of lattice vacancies in the Ni and Si sites. The detailed studies of heat capacity as well as dc and ac magnetization including different non-equilibrium dynamical behaviour, viz., aging effect, temperature and field dependent magnetic relaxation and magnetic memory effect establish the compound to be a cluster-glass material having a spin freezing temperature ∼6.6 K. To understand the nature of the glassy phase, experimental results have been analysed using a few different theoretical models and found that the observed magnetic memory effect favours the hierarchical model over the droplet model. Competing exchange interaction driven magnetic phase inhomogeneity could be further confirmed through exchange bias effect. The observed magnetic phase inhomogeneity has been attributed to random magnetic anisotropy that develops due to local environmental variations between the rare-earth ions.