Enhanced magnetism of Cun clusters capped with N and endohedrally doped with Cr

Abstract

The focus of our work is on the production of highly magnetic materials out of Cu clusters. We have studied the relative effects of N-capping as well as N mono-doping on the structural stability and electronic properties of the small Cu clusters using first principles density functional theory based electronic structure calculations.We find that the N-capped clusters are more promising in producing giant magnetic moments, such as 14 µB for the Cu6N6 cluster and 29 µB for the icosahedral Cu13N12 clusters. This is accompanied by a substantial enhancement in their stability. We suggest that these giant magnetic moments of the capped Cun clusters have relevance to the observed room temperature ferromagnetism of Cu doped GaN. For cage-like hollow Cu-clusters, an endohedral Cr-doping together with the N-capping appears as the most promising means to produce stable giant magnetic moments in the copper clusters.

A Systematic Investigation on CrCun Clusters with n = 9–16: Noble Gas and Tunable Magnetic Property

“…At the final stage, one can achieve the icosahedral CrCu 12 structure by directly adding one Cu atom to the pentagonal face of 11.A. Our finding icosahedral geometry for the minimum-energy CrCu 12 is in line with previous work. , The growth of larger clusters is based on the CrCu 12 core. In particular, the CrCu 13 cluster appears in form of CrCu 12 capped by one additional Cu atom.…”

“…It is known that the Cr dopant is magnetic element having 7 S 3 state due to its unpaired 4s 1 3d 5 valence electrons. In this case, copper clusters are often be considered as a host that provides n delocalized 4s 1 electrons, having zero magnetic moment at even sizes while odd-numbered sizes possessing a value of 1 μ B . ,, While the odd–even staggering behavior has been observed for the magnetic ground states of pure Cu clusters, the Cr dopant has apparently altered the magnetic moment of doped species in a systematical manner.…”

“…Among TM dopants, Cr appears as a special case. Previous studies showed that doping Cr likely stabilizes copper clusters and the local magnetic moment of Cr impurities can be quenched in a Cu 12 host. − In addition, clusters of copper doped with Cr, like other mixed TM-copper systems, might offer structural evolutions that are very different from their pure counterparts. Unfortunately, the origin of such a magnetic quenching and size-dependent properties of CrCu n clusters have not been thoroughly discussed so far.…”