Magnetic excitations and - hybridization effect in PrTiAl and PrVAl

Tokunaga, Yo  ; Sakai, Hironori   ; Kambe, Shinsaku  ; Sakai, Akito*; Nakatsuji, Satoru*; Harima, Hisatomo*

By means of Al NMR studies, we have investigated magnetic excitations and the hybridization effect between Pr 4 and conduction electrons in a pair of cubic compounds PrAl (=Ti, V). From Knight shift measurements we have evaluated comparative strengths for the - hybridization effect in these compounds and confirm a definite increase of hybridization on replacing Ti with V. Analysis of the spin-lattice relaxation rate reveals that the spectral width of magnetic fluctuations in crystalline electric field excited states is strongly temperature dependent. This result indicates that magnetic fluctuations are dominated by the strong - exchange coupling at high temperatures and thus is nicely consistent with the Kondo picture that features ln dependence of resistivity over the same temperature region.