Effect of reentrant spinglass-like states on Schottky Anomaly and exchange bias in polycrystalline Sm0.5Y0.5Fe0.58Mn0.42O3

The specific-heat and exchange bias effects in polycrystalline Sm _0.5Y _0.5Fe _0.58Mn _0.42O ₃ [SYFM (58–42)] have been investigated within the temperature interval of 2–300 K . Specific-heat measurements as a function of temperature have revealed a sizable linear contribution at low temperature that may be associated with the glassy magnetic ordering, alongwith a diffused Schottky peak over a wide temperature range between 2 and 20 K. The observed distribution of Schottky levels is explained by the inhomogeneity of the molecular field in the spinglass (SG) state that leads to variable splitting of the Kramer’s ground-state doublets in Sm ^{3 +} ions. A finite zero field exchange bias (EB) effect have been observed at low temperatures for T < 70 K. The field dependency of the exchange bias showed the tuning of the sign of EB that can be attributed to the competition of the interfacial exchange bias and atomic EB arising from the cooling field induced anisotropy of the weak ferromagnetic moments of the constituent ions of Fe ³⁺/Mn ³⁺. .