Ferromagnetism of 3He films in the low-field limit.
We provide evidence for a finite-temperature ferromagnetic transition in two dimensions as H -->0 in thin films of 3He on graphite, a model system for the study of two-dimensional magnetism. We perform pulsed and cw NMR experiments at fields of 0.03-0.48 mT on 3He at areal densities of 20.5-24.2 atoms/nm(2). At these densities, the second layer of 3He has a strongly ferromagnetic tendency. With decreasing temperature, we find a rapid onset of magnetization that becomes independent of the applied field at temperatures in the vicinity of 1 mK. Both the dipolar field and the NMR linewidth grow rapidly as well, which is consistent with a large (order unity) polarization of the 3He spins.
Bozler
H M
HM
Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA.
Gu
Yuan
Y
Zhang
Jinshan
J
White
K S
KS
Gould
C M
CM