Temperature chaos in a Ge:Mn thin-film spin glass

Temperature changes in thin-film Ge: Mn spin-glass dynamics are presented that exhibit temperature chaos (TC) when the spin-glass correlation length (t, T) grows to its thickness L. For small L15. 5 nm, the transition to chaos takes place over a temperature range sufficiently large to exhibit both reversible and chaotic behavior. The value of can be related to the critical exponent for TC,. Experimentally, is found to be 1. 06, in the range of recent simulations. The presence of a specific length scale L allows the transition to chaos to be examined over measurable laboratory temperature changes. The transition is found to be abrupt. Bulk materials, with a distribution of crystallite sizes, will smear out the transition, resulting in a very slow crossover. The abruptness of the transition and its nature are compared with recent theoretical calculations.