A nuclear magnetic resonance study of SmMn2H2
Abstract A 147 Sm and 149 Sm nuclear magnetic resonance study of the hydride SmMn 2 H 2 at 4.2 K is reported. Well resolved quadrupole septets are observed in the spectra of both isotopes. The value of the hyperfine field, 342.7 T, corresponds with the fully polarised magnetic state, J z = J =5/2, of samarium in the compound. The magnitude of the electric field gradient derived from the line separation in the spectra and the quadrupole oscillations of the spin echo decay curves reveals a considerable lattice contribution to the electric field gradient. The results are discussed in terms of the influence of hydrogen on the contribution of Sm to the magnetocrystalline anisotropy of the compound and a conclusion about the magnetic structure of the compound is given.
I discuss recent developments in the study of cosmological limits on the Minimal Supersymmetric Standard Model (MSSM). In particular, I focus on the effect of neutralino-stau coannihilation on the relic abundance of neutralinos, and I give examples where the cosmologically derived limits on the supersymmetric parameters are relaxed, and one example (CP violating phases) where they are not.