The local effect of an interstitial hydrogen-like particle on localized f electrons was studied in PrPb3 by means of μ+ spin rotation and relaxation. Spontaneous μ+ spin precession with harmonic frequencies was observed for the first time in f electron compounds. It was demonstrated that the signal was derived from a coupling between the μ+ spin and the hyperfine-enhanced nuclear spin of nearest neighbour (NN) 141Pr with Ising-like anisotropy. The signal also suggests a marked suppression of spin dynamics of the NN 141Pr in comparison with that of the bulk 141Pr. These facts strongly indicate modification of the f electronic state due to the interstitial charged particle.

Quantized Hyperfine Field at an Implanted Μ+ Site in PrPb3 - Interplay between Localized f Electrons and an Interstitial Charged Particle. T.U.Ito, W.Higemoto, K.Ohishi, N.Nishida, R.H.Heffner, Y.Aoki, A.Amato, T.Onimaru, H.S.Suzuki: Physical Review Letters, 2009, 102[9], 096403