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キーワード:
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要旨:
Fe-57 nuclear forward scattering on the chiral magnet FeGe reveals an
extremely large precursor phase region above the helimagnetic ordering
temperature T-C(p) and beyond the pressure-induced quantum phase
transition at 19 GPa. The decrease of the magnetic hyperfine field <
B-hf > with pressure is accompanied by a large increase of the width of
the distribution of < B-hf >, indicating a strong quasistatic
inhomogeneity of the magnetic states in the precursor region. Hyperfine
fields of the order of 4 T (equivalent to a magnetic moment mu(Fe)
approximate to 0.4 mu(B)) persist up to 28.5 GPa. No signatures of
magnetic order have been found at about 31 GPa. The results, supported
by ab initio calculations, suggest that chiral magnetic precursor
phenomena, such as an inhomogeneous chiral-spin state, are vastly
enlarged due to increasing spin fluctuations as FeGe is tuned to its
quantum phase transition.
