Effect of Exchange Interactions on the Coercivity of SmCo₅ Nanoparticles Made by Cluster Beam Deposition

Abstract

Abstract Single crystal SmCo 5 nanoparticles with an average size of 3.5 nm are produced by cluster‐beam deposition. When deposited without matrix, the nanoparticles showed a super‐paramagnetic behavior with a blocking temperature of 145 K. Dispersion of the SmCo 5 nanoparticles in a carbon matrix results in an increase in both the coercivity and the blocking temperature. Room temperature coercivities as high as 12 kOe are obtained for the first time in mono‐layers of SmCo 5 nanoparticles dispersed in C matrix. δM plots show that the interactions in the samples are of exchange type, which can decrease the overall effective anisotropy and coercivity according to the random‐anisotropy model. Coercivity is found to be inversely proportional to the packing density of the particles. SmCo 5 nanoparticles with high coercivity are potential candidates for the next generation ultra high‐density magnetic recording media.