Magnetic Correlations in Nanocomposite FePt:Au and FePt:C Films

Authors

Thomas A. George, University of Nebraska-LincolnFollow
Ralph Skomski, University of Nebraska-LincolnFollow
David J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

2009

Comments

Published in JOURNAL OF APPLIED PHYSICS 105, 07B736 (2009). Copyright © 2009 American Institute of Physics. Used by permission.

Abstract

The nanostructure and magnetism of L1₀-ordered FePt crystallites in matrices of Au and C are investigated as a function of the Au and C contents. Emphasis is on the relation between hysteresis-loop shape, magnetic correlation length, and structural disorder, as relevant to magnetic recording media. The highly (001) textured thin films are produced by annealing [Fe&#;&#;Pt&#;X]_n multilayers. The coercivity and the hysteresis-loop slope at coercivity increase and decrease, respectively, with increasing volume fraction of the matrix. The magnetic force microscopy images show that the slope decrease is accompanied by a reduction in the magnetic correlation length. These changes are due to the reduced intergranular exchange coupling, and a simple model describes how interparticle exchange cooperatively increases both the loop slope and the correlation length.