Spin glass or random anisotropy?: The origin of magnetically glassy behavior in nanostructured GdAl₂

Authors

P. M. Shand, University of Northern IowaFollow
C. C. Stark, University of Northern Iowa
D. Williams, University of Nebraska-Lincoln
Marco Morales Torres, University of Nebraska - LincolnFollow
T. M. Pekarek, University of North FloridaFollow
Diandra Leslie-Pelecky, University of Nebraska -- LincolnFollow

Date of this Version

5-15-2005

Comments

Published by American Institute of Physics. J. Applied Physics 97, 10J505 (2005). ©2005 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

Initially crystalline GdAl₂ was mechanically milled for long times to produce a highly chemically disordered phase with approximately 8-nm grains. Analysis of dc magnetization measurements using an Arrott plot and the approach to saturation suggest the presence of significant random anisotropy. ac susceptibility measurements showed that the shift in the peak temperature with frequency usually seen in magnetically glassy and superparamagnetic systems was virtually undetectable in the 10–1000-Hz frequency range. Based on these results, we believe that this material represents an interacting system with random anisotropy, where the anisotropy is the result of surface and interface asymmetries. ©2005 American Institute of Physics