NMR Of Cu Satellites in the Kondo Alloy CuCr

摘要

Using pulsed NMR techniques, resonances of Cu nuclei which are near neighbors to Cr impurities (c = 100 and 200 ppM) in CuCr (theta/sub k/ approx. 3K) have been studied in the temperature range 1 to 4K and applied fields H sub 0 = 20 to 125 kOe. At the highest fields and lowest temperatures the satellite shifts approach saturation. Above approx. 40 kOe the spin-lattice relaxation rate T sub 1-1 is proportional to T/H sub 02 , indicating that the dominant relaxation mechanism arises from transverse fluctuations of a polarized local moment. The measured rates yield a local-moment/conduction-electron exchange interaction vertical bar J sub 0 vertical bar/g = 0.30, where g is the Cr g-value. Below approx. 40 kOe T sub 1-1 appears to be slightly enhanced in comparison with the high-field behavior, but becomes field independent below approx. 30 kOe. Both effects are attributed to Kondo anomalies. (ERA citation 04:027090)