UC Irvine

We report the results of a 11B nuclear magnetic resonance (NMR) study of SrB6 at temperatures between 0.1 and 30 K and in a magnetic field of 4.74 T. Below 30 K the NMR spectrum is temperature independent but the spin-lattice relaxation rate T1-1 exhibits different features in two different temperature regimes. At high temperatures, between 30 K and a field-dependent crossover temperature TB between 0.5 and 2 K, T1-1 is almost temperature independent. We point out that for T in the crossover temperature range the magnitude of T1l-1 of SrB6 is distinctly larger than for LaB6, a metal with a charge carrier concentration at least two orders of magnitude higher than that of SrB6. A possible cause for this behavior maybe the very weak itinerant ferromagnetism that has subsequently been established to occur in nominally pure SrB6. At low temperatures, below TB, T1-1 decreases substantially with decreasing temperature confirming a cross-over or phase transition phenomenon as observed by measurements of thermal and transport properties. © 2000 Elsevier Science B.V. All rights reserved.