Identification of local spin fluctuations by weak localization

While some 3d impurities in a metal host possess a magnetic moment, the majority of d impurities are nonmagnetic at low temperatures. This can be due to the Kondo effect or local spin fluctuations (LSF's). We present two experimental examples for LSF's and show that weak localization is an excellent tool to investigate LSF's. The LSF's are enhanced by the Stoner factor due to the exchange interaction. This enhancement of the LSF's causes a dephasing of the conduction electrons. The dephasing is proportional to the temperature and can be measured by weak localization.