Spin fluctuations probed by NMR in paramagnetic spinelLiV2O4: a self-consistent renormalization theory

Abstract

Low-frequency spin fluctuation dynamics in paramagnetic spinelLiV2O4, a rare 3d-electron heavy-fermion system, is investigated. A parametrizedself-consistent renormalization (SCR) theory of the dominant AFM spin fluctuations isdeveloped and applied to describe temperature and pressure dependences of thelow-T nuclear spin–latticerelaxation rate 1/T1 in this material. The experimental data for1/T1 availabledown to ∼1 K are well reproduced by the SCR theory, showing the development of AFM spin fluctuationsas the paramagnetic metal approaches a magnetic instability under the applied pressure. Thelow-T upturn of 1/T1T detected below 0.6 K under the highest applied pressure of 4.74 GPa isexplained as the nuclear spin relaxation effect due to the spin freezingof magnetic defects unavoidably present in the measured sample ofLiV2O4.