Magnetoresistance in CoFe_2O_4/BiFeO_3 core-shell nanoparticles near room temperature

摘要

A systematic study of near room temperature magnetoresistance (MR) behavior is carried out for magnetoelectric CoFe2O4-BiFeO3 core-shell nanoparticles. The analysis of MR data reveals that the MR is guided by the anisotropic magnetoresistance (AMR) and the giant magnetoresistance (GMR) effect. The GMR effect is predominant in the sample having a maximum shell thickness, whereas the AMR effect dominates the least shell thickness and bare CoFe2O4. Analysis of the MR data in conjunction with the resistivity suggests that the electrical conduction in these samples is due to (a) tunneling and (b) hopping of electrons across the domains. The impedance and modulus spectra analysis shows that the core-shell particles as a whole are participating in the relaxation process, thus indicating a strong coupling between the core and shell, which may be highly desirable while fetching their magnetoelectric based applications. Published by AIP Publishing.