Anomalous NMR Spin-Lattice Relaxation in SrB_{6} and Ca_{1-x}La_{x}B_{6}

Abstract

We report the results of {11}B nuclear magnetic resonance (NMR) measurements of SrB_{6} and Ca_{0.995}La_{0.05}B_{6} below room temperature. Although the electrical resistivities of these two materials differ substantially, their {11}B-NMR responses exhibit some strikingly common features. Both materials exhibit ferromagnetic order, but their {11}B-NMR spectra reveal very small hyperfine fields at the Boron sites. The spin lattice relaxation T_{1}^{-1} varies considerably with external field but changes with temperature only below a few K. We discuss these unusual results by considering various different scenarios for the electronic structure of these materials.

arXiv commentAccepted for publication in Phys. Rev. B Rapid communication, 4 pages, 3 figures. This manuscript replaces an earlier version and includes some minor changes in the text and in Fig. 2

References in corpus (2)

• Excitonic ferromagnetism in the hexaborides
• Electronic Fine Structure in the Electron-Hole Plasma in SrB6

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