Exchange bias effect and exchange spring-type behavior of core-shell structured MnFe2O4/α-Fe2O3 nanocomposite systems

Abstract

In this article, we have explored the exchange coupled behavior of MnFe2 O4 /α -Fe2 O3 core-shell based nanocomposite systems. Four nanocomposite samples were prepared by varying weight percentage of α -Fe2 O3 with the generic formula (1 − x ) MnFe2 O4 /x α -Fe2 O3 (x = 0.15, 0.30, 0.45 and 0.60). The existence of single spinel cubic phase of MnFe2 O4 along with rhombohedral phase of α -Fe2 O3 was verified by the X-ray powder diffraction profiles. The FC hysteresis loops disclosed a large amount of exchange bias (H EB ) of 1.1 kOe along with high coercivity (3.3 kOe) at 5 K for all the samples. Exchange spring type behavior was observed in hysteresis curves of entire nanocomposites. The M-T plots revealed that the blocking temperature (T B ) of entire samples was above the room temperature together with presence of strong interparticle interactions. The blocking temperature was found to shift above 300 K even in tiny size due to significant exchange bias effect.