Orbital magnetism in transition-metal clusters:: From Hund's rules to bulk quenching -: art. no. 226402

The local and average orbital moments of transition-metal (TM) clusters are determined bridging the gap between atomic Hund's rules and solid-state quenching. A remarkable enhancement of is revealed in agreement with recent measurements. In small Ni-N (Nless than or equal to10), represents (20-40)% of the total magnetization and is therefore crucial for the comparison between theory and experiment. Larger clusters (Ngreater than or equal to150) show nearly bulklike quenching at the interior but retain a considerable surface enhancement. Trends for different TM's are discussed.