From: Arthur F. Hebard <afh@phys.ufl.edu> Date: Mon, 6 May 2002 22:40:49 GMT (237kb)
Authors:
N. Theodoropoulou,
A. F. Hebard,
M. Gabay,
A. K. Majumdar,
C. Pace,
J. Lannon,
D. Temple
Comments: 5 pages, 4 figures
Subj-class: Materials Science
Using temperature-dependent magnetoresistance and magnetization measurements on Fe/Cr multilayers that exhibit pronounced giant magnetoresistance (GMR), we have found evidence for the presence of a glassy antiferromagnetic (GAF) phase. This phase reflects the influence of interlayer exchange coupling (IEC) at low temperature (T < 140K) and is characterized by a field-independent glassy transition temperature, Tg, together with irreversible behavior having logarithmic time dependence below a "de Almeida and Thouless" (AT) critical field line. At room temperature, where the GMR effect is still robust, IEC plays only a minor role, and it is the random potential variations acting on the magnetic domains that are responsible for the antiparallel interlayer domain alignment.