Effect of finite mean free path on spin-flip scattering rates near the critical point of magnetically ordered systems

Abstract

The finite electron mean free path of conduction electrons is found to play an important role in determining spin-flip scattering rates, 1/sf, near a magnetic critical point. Small-momentum-transfer processes are suppressed and the temperature dependence of 1/sf is dominated by large-momentum scattering. For TTc, 1/sf is monotonically increasing and its leading singular temperature dependence varies at t1-, where t=(T-Tc)/Tc. This temperature dependence is also present for TTc, but for Heisenberg systems, of present interest, the leading singular term varies as (-t)2--, where is the crossover exponent