Europhys. Lett.
Volume 66, Number 6, June 2004
Page(s) 847 - 853
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 June 2004
Europhys. Lett., 66 (6) , pp. 847-853 (2004)
DOI: 10.1209/epl/i2003-10261-5

On temperature chaos in Ising and XY spin glasses

F. Krzakala

Dipartimento di Fisica, INFM and SMC, Università di Roma "La Sapienza" P.le A. Moro 2, 00185 Roma, Italy

(Received 12 November 2003; accepted in final form 14 April 2004)

We argue that the chaotic temperature effect predicted in Ising spin glasses should be stronger when one considers continuous ( XY, Heisenberg) kind of spins, due to bigger entropic fluctuations. We then discuss the behavior of 3d spin glasses using the Migdal-Kadanoff Renormalization Group for Ising and XY spins, where we show explicitly that the chaotic length scale, the length beyond which equilibrium configurations are completly reshuffled when one changes temperature, could be far smaller for XY than for Ising spins. These results could thus explain why experiments are seeing a stronger rejuvenation effect for continuous spins.

75.10.Nr - Spin-glass and other random models.
05.50.+q - Lattice theory and statistics (Ising, Potts, etc.).
75.60.Nt - Magnetic annealing and temperature-hysteresis effects.

© EDP Sciences 2004