The Anomaly in the Knight Shift vs Susceptibility Plot of ³¹P NMR in (Ce_xLa_1-x)P

Systematic ³¹P NMR studies have been made on (Ce_xLa_1-x)P (x = 1.00, 0.90, 0.10, 0.02) using powders obtained from high-quality single crystals. For CeP, previously reported strong non-linearity of the Knight shift vs susceptibility plot, with an order of magnitude larger coupling constant A_THI of the transferred hyperfine interaction (THI) at higher temperatures than at lower temperatures, has been confirmed to be an intrinsic property. For mixed systems, NMR spectra are composed of almost equally spaced several peaks. Detailed analyses of the spectra have shown that only the 1st-nearest-neighbor Ce ions contribute dominantly to the THI of ³¹P in both the dense (x = 1.00, 0.90) and the dilute (x = 0.10, 0.02) systems. Despite this short-ranged THI, A_THI varies dramatically between the two systems in quite a different way for the lower and the higher temperatures. Hence the large difference between the lower-T the higher-T A_THI in CeP becomes only a factor of ∼1.7 difference in the dilute systems.