Weak itinerant antiferromagnetism in PuIn3 explored using 115In nuclear quadrupole resonance

Abstract

The results of 115In nuclear quadrupole resonance (NQR) measurements on PuIn3 are reported. Three of the four NQR lines of 115In expected for nuclear spin I = 9/2 are observed. The equal spacing of these lines at 20 K yields the NQR frequency of νQ = 10.45 MHz, and the asymmetry parameter of the electric field gradient η = 0. The NQR line profile and the nuclear spin–lattice relaxation rate 1/T1 display an abrupt change at 14 K, which is associated with the onset of long-range antiferromagnetic order. The temperature dependences of the staggered magnetization MQ(T), extracted from the NQR spectra, and 1/T1 below TN = 14 K are well explained by the self-consistent renormalization (SCR) theory for spin fluctuations. In addition, the scaling between T1T and MQ(T)/MQ(0) is also consistent with the predictions of SCR theory, providing further evidence that PuIn3 is a weak itinerant antiferromagnet in which spin fluctuations around the antiferromagnetic wavevector play a major role in the system’s behavior at finite temperatures.