Effect of carbon encapsulation on magnetic inter-particle interaction of iron nanoparticles

Abstract

Carbon encapsulation of magnetic nanoparticles reduces agglomeration and makes the nanoparticles stable. In this work, as-prepared carbon-coated iron nanoparticles (CCFeNPs) are treated with hydrogen peroxide (H2O2) solution, and the effect of carbon coating on the interparticle interaction of iron nanoparticles is discussed. Morphological characterization and the magnetization data confirmed that the treatment removes some coating layers. Field cooled (FC) and zero-field cooled (ZFC) measurements on the two samples revealed that the blocking temperature (TB) of the treated sample is lowered post hydrogen peroxide treatment. Magnetic interaction is increased in the treated sample compared to the as-prepared one and follows the Morup–Tronc (MT) model of inter-particle interactions (IPI). MR/MS ratio decreases post-treatment, indicating an increase in IPI after treatment. Out-of-phase AC susceptibility data showed two slope changes; one at a higher temperature indicates the magnetic blocking of core Fe, and the other at a lower temperature with a broad peak that shifts with frequency due to spin-glass behavior in the system.