SR evidence of nonmagnetic order and Pr hyperfine-enhanced nuclear magnetism in the cubic ground doublet system PrTiAl

Ito, Takashi   ; Higemoto, Wataru  ; Ninomiya, Kazuhiko; Luetkens, H.*; Baines, C.*; Sakai, Akito*; Nakatsuji, Satoru*

A muon spin relaxation (SR) study of the cubic ground doublet system PrTiAl is presented. The zero-field SR rate shows no significant change while passing through the phase transition temperature = 2.0 K, indicating that a nonmagnetic order parameter lies behind the ordered state. This is consistent with a ferroquadrupole ordering scenario standing on quadrupole degrees of freedom active in the subspace. We also found that slow spin fluctuations remain even at 0.1 K well below , ascribed to Pr hyperfine-enhanced nuclear magnetism in the nonmagnetic ground state. The electronic exchange constant and Pr nuclear order temperature were estimated to be 0.64 K in the temperature unit and 0.13 mK, respectively, from the Pr nuclear spin fluctuation frequency 5.8(2) MHz at 0.1 K.