Quantum hall ferromagnetism in a two-dimensional electron system
Experiments on a nearly spin degenerate two-dimensional electron system reveals unusual hysteretic and relaxational transport in the fractional quantum Hall effect regime. The transition between the spin-polarized (with fill fraction nu = 1/3) and spin-unpolarized (nu = 2/5) states is accompanied by a complicated series of hysteresis loops reminiscent of a classical ferromagnet. In correlation with the hysteresis, magnetoresistance can either grow or decay logarithmically in time with remarkable persistence and does not saturate. In contrast to the established models of relaxation, the relaxation rate exhibits an anomalous divergence as temperature is reduced. These results indicate the presence of novel two-dimensional ferromagnetism with a complicated magnetic domain dynamic.
Eom
J
James Franck Institute and Department of Physics, University of Chicago, Chicago, IL 60637, USA. Department of Electrical Engineering, University of California at Santa Barbara, Santa Barbara, CA 93106, USA. Walter Schottky Instit.
Cho
H
Kang
W
Campman
KL
Gossard
AC
Bichler
M
Wegscheider
W