Curie–Weiss analysis of ferromagnetic and glassy transitions in nanostructured GdAl₂

Authors

• D. Williams, University of Nebraska–Lincoln
• P. M. Shand, University of Northern IowaFollow
• C. Stark, University of Northern Iowa
• T. Pekarek, University of North FloridaFollow
• R. Brown, University of Nebraska–Lincoln
• Lanping Yue, University of Nebraska–LincolnFollow
• Diandra Leslie-Pelecky, University of Nebraska -- LincolnFollow

Document Type

Article

Date of this Version

5-15-2003

Comments

Published by American Institute of Physics. J. Applied Physics 93, 6525-6527 (2003). ©2003 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

Structural inhomogeneity on length scales comparable to magnetic interaction lengths can produce complex magnetic behavior. Crystalline GdAl₂ is a ferromagnet with a Curie temperature of 170 K, while amorphous GdAl₂ thin films exhibit classic spin-glass behavior with a freezing temperature of 16 K. Nanostructured GdAl₂, made by mechanically milling initially crystalline GdAl₂, exhibits ferromagnetic and spin-glass-like transitions; however, the spin-glass-like transition occurs at a higher temperature than the freezing temperature of amorphous GdAl₂ thin films. Curie–Weiss analysis suggests that the paramagnetic-to-ferromagnetic transition is due to the ferromagnetic ordering of small GdAl₂ clusters and that the glassy transition is most likely due to spin-glass-like ordering of a surface/interface phase. ©2003 American Institute of Physics.