Core/shell architecture as an efficient tool to tune DC magnetic parameters and AC losses in spinel ferrite nanoparticles

Effect of shell thickness on DC magnetic parameters (saturation magnetization, coercivity, blocking temperature) and AC losses (specific loss power, intrinsic loss power) has been studied for Fe3O4/CoFe2O4 core/shell-like magnetic nanoparticles with a fixed diameter of core similar to 6.3 nm and an effective thickness of shell up to 2.5 nm. Regularities of the transformation of magnetic hysteresis loop parameters upon the increase in shell thickness have been analyzed and related to the intrinsic parameters of the core, shell and core-shell interfacial region. The values of specific/intrinsic loss power have been determined from experiment and compared with those calculated from the area of magnetic hysteresis loops. It is shown that the addition of 1 nm CoFe2O4 shell to the Fe3O4 core strongly enhances heating efficiency of the obtained composite nanoparticles. It is concluded that employment of core/shell-like architecture paves the way to tune and optimize the parameters of spinel ferrite nanoparticles. (c) 2019 Elsevier B.V. All rights reserved.