Magnetic state of f electrons in δ-phase of Pu–Ga alloys studied by Ga NMR

69Ga nuclear magnetic resonance (NMR) line shift (69K) and nuclear spin–lattice relaxation rate (69T1−1) are measured for Pu0.95Ga0.05 alloy, stabilized in δ-phase, in the temperature range 10 and 650 K at magnetic field of 9.4 T. The shift and 69T1−1 are determined correspondingly by the static and fluctuating-in-time parts of the local magnetic fields arisen at Ga due to transferred hyperfine coupling with the nearest f electron environment of more magnetic Pu. At T > 200 K, the temperature dependent part of the shift 69K(T) scales macroscopic magnetic susceptibility χ(T), following the Curie–Weiss law, and the product (69T1T) increases with temperature proportionally (T + 255)1.5(1). Both of the NMR observations are typical of the incoherent spin fluctuation regime of f electrons in nonmagnetic 3D Kondo lattice. An estimate of the effective magnetic moment μeff,5f(ge = 2) = 0.15(5)μB per Pu atom points out a strong suppression of the spin magnetism in the alloy.