We report the NQR study on the pressure-induced paramagnetic state in the antiferroinagrietic (AF) intermetal-lic compound YMn2 with the Néel temperature TN=100 K at ambient pressure. Froin the T variation of the nuclear spin-lattice relaxation rate, 56(lJT1) of 55Mn above the critical pressure of 4 kbar, the spin fluctuation feature is found to change below a temperature Taf. At higher temperature than Taf, the nuclear relaxation behavior is well described in terms of the self-consistent renomalized (SCR) spin fluctuation theory for nearly AF metals, whereas below Taf a deviation is significant and 1JT1T exhibits a weak T variation. It is pointed out that Taf coincides with the temperature below which a T2 law in electrical resistivity is valid as expected for a Feimi liquid ground state. We proposed that these features are understood from the standpoint that the development of AF spin fluctuation remains in short-range associated with the singlet formation among Mn spins in each tetrahedron as suggested by the inelastic neutron experiments on Y1−xScxMn2.
|Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu
|Published - 1998
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