Quenched disorder/impurity

There exists a second way to obtain the effective Hamiltonian (21). A weak quenched disorder term can be introduced directly into the effective Hamiltonian (13). The presence of non-magnetic impurities in a microscopic model (15) manifests itself in fluctuations of the local temperature of the phase transition. Introducing = V ( ) the field of loccd critical temperature fluctuations, one obtains the effective disordered Hamiltoni ln [53] ... 

We have seen that dissipation can lead to an effective long-range interaction in time and thus break the symmetry between space and time directions in the last example. Another mechanism to break this symmetry is quenched disorder (i.e., impurities and defects), because this disorder is random in space but perfectly correlated in the time direction. 

Other factors snch as cold deformation and processing conditions can affect resistivity. The cold deformation effect is not as pronounced as the addition of impurity or alloying elements, but the effect of processing on resistivity can be large, as illustrated in Figure 6.5 for a CU3AU compound. The effect on resistivity is again related to strnctnre. The rapidly quenched componnd maintains its disordered structure, which... 

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