Theoretical study of structural, electronic and magnetic properties of Co clusters embedded in an Ag matrix

We present a theoretical study investigating small Co nano-clusters embedded within an Ag matrix using Density Functional Theory. The calculations were conducted using the freely distributed SIESTA code, employing the generalized gradient approximation for the exchange and correlation potential. Our study focuses on Com clusters of specific sizes (m = 1 to 6, 8, 10, 13, and 19) embedded in an Ag bulk matrix. Our results reveal that the embedded Co clusters exhibit a magnetic signal distinct from that of the Co-bulk system. The calculated structural and electronic properties provide the following insights: (a) The Co clusters exhibit a preference for segregated and compact structures within the Ag matrix, with segregation prevailing over the mixing process; (b) The CoAg system demonstrates magnetic behavior across all Co cluster sizes, displaying a smooth decrease as the size increases, eventually approaching the magnetic value of Co in bulk; (c) The transfer of charge between Ag and Co is negligible. Theoretical results derived from our calculations offer a microscopic understanding of the physical processes occurring within the system. We hope that our findings will inspire experimental groups to verify and validate our observations.