Exchange bias and magnetic memory effect in hole doped Nd0.78Sr0.22CoO3 nanoparticles

Abstract

Nd_0.78Sr_0.22CoO₃ nanoparticles having 89 nm average particle size are synthesized by standard sol–gel techniques. Structural and morphological characterization is performed by X-ray diffraction and FESEM images. DC magnetization studies in the range 1.6 K to 300 K reveal the disordered magnetic phase below 36 K. Existence of this disordered magnetic phase is substantiated by the magnetic memory effect. A significant upturn in the ZFC magnetization below 4.5 K, which is a signature of a dominant ferromagnetic (FM) component, is observed. This FM component may be attributed to the uncompensated (UC) spins at the surface of Nd_0.78Sr_0.22CoO₃ nanoparticles. The presence of the interface of these two magnetic components with significantly different anisotropy results in the exchange bias effect.