Evidence of transition between Heisenberg and Ising-like phases in mesoscale Ge:Mn spin glass

The glassy dynamics of vector spin glasses in presence of a weak uniaxial anisotropy has been a subject of longstanding controversy. It has been predicted that in presence of such anisotropy Heisenberg-like spin glass system first undergoes longitudinal moment freezing, followed by a transverse moment freezing at even lower temperature. Evidence of such phase transition is seen in the temperature chaos experiments in thin film Ge:Mn spin glass. Here the sample temperature is increased from the quench temperature after the correlation length has reached its thickness. For large enough positive change of temperatures the maximum barrier height increases monotonically, which is consistent with a phase change of lower temperature Heisenberg-like phase to higher temperature Ising-like phase.