Unusual spin correlations in a nanomagnet

Authors

Balamurugan Balasubramanian, University of Nebraska-LincolnFollow
Priyanka Manchanda, University of Nebraska-LincolnFollow
Ralph Skomski, University of Nebraska at LincolnFollow
Pinaki Mukherjee, University of Nebraska-LincolnFollow
Bhaskar Das, University of Nebraska-LincolnFollow
T A. George, University of Nebraska-LincolnFollow
George C. Hadjipanayis, University of DelawareFollow
David J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

2015

Citation

APPLIED PHYSICS LETTERS 106, 242401 (2015)

Comments

Copyright 2015 Used by permission

Abstract

We show how atomic-scale exchange phenomena can be controlled and exploited in nanoscale itinerant magnets to substantially improve magnetic properties. Cluster-deposition experiments, first-principle simulations, and analytical calculations are used to demonstrate the effect in Co2Si nanoclusters, which have average sizes varying from about 0.6 to 29.5 nm. The cluster-deposited nanoparticles exhibit average magnetic moments of up to 0.70 lB/Co at 10K and 0.49 lB/Co at 300K with appreciable magnetocrystalline anisotropies, in sharp contrast to the nearly vanishing bulk magnetization. The underlying spin correlations and associated cluster-size dependence of the magnetization are explained by a surface induced ferromagnetic spin polarization with a decay length of the order of 1 nm, much larger than the nearest-neighbor interatomic distance in the alloy.