Springer Verlag, Hyperfine Interactions, 1-3(197), p. 135-141
DOI: 10.1007/s10751-010-0222-3
HFI / NQI 2010, p. 135-141
DOI: 10.1007/978-94-007-1269-0_25
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Annealed (H1) and cold-rolled (H2) HAVAR has been studied using high-pressure synchrotron X-ray diffraction. A structural phase transformation was discovered at ∼13 GPa at ambient temperature, transforming from m −3 m (S.G. 225) to P 63/m m c (S.G. 194) symmetry. The transition was not reversible on pressure release. The low-pressure cubic phase was found to be more compressible than the high-pressure hexagonal phase. Conventional Mössbauer and NFS shows that the HAVAR is not magnetic at room temperature and no splitting is observed. The SQUID indicates a huge difference in the temperature dependence of the magnetic susceptibility between the cold Rolled HAVAR compared to the annealed HAVAR.