139La NMR studies in LaIn3
Abstract
Normal-state nuclear magnetic resonance studies of the superconductor LaIn3 have been made in order to investigate the origin of the large temperature-dependent normal-state susceptibility χ attributed to exchange enhancement of the La d-electron spin susceptibility. The 139La Knight shifts, linewidth, and nuclear-spin relaxation times (T1 and T2) have been measured with cw and pulsed techniques from 1.6°K to 300°K. The Knight shifts (+0.402%±0.002% at 1.6°K-+0. 371%±0.002% at 300°K) vary linearly with χ. The relaxation times vary from T1T = 1.1±0.05 sec°K at 4.2°K to T 1T = 1.6±0.1 sec°K at 300°K. The small magnitude and temperature dependence of the La T1 and Knight shift as well as the value of the Korringa product K2T1T/S of 1.28 at 4.2°K appears in the independent band approximation to be inconsistent with the expected large La d-band hyperfine contribution. This suggests a breakdown of the independent band approximation in LaIn3 due to interference effects between the various hyperfine interactions. © 1971 The American Institute of Physics.