First-order transition in the spin dynamics of geometrically frustrated Yb2Ti2O7.
نویسندگان
چکیده
Using neutron diffraction, 170Yb Mössbauer and muon spin relaxation spectroscopies, we have examined the pyrochlore Yb2Ti2O7, where the Yb3+S' = 1/2 ground state has planar anisotropy. Below approximately 0.24 K, the temperature of the known specific-heat lambda transition, there is no long range magnetic order. We show that the transition corresponds to a first-order change in the fluctuation rate of the Yb3+ spins. Above the transition temperature, the rate, in the GHz range, follows a thermal excitation law, whereas below, the rate, in the MHz range, is temperature independent, indicative of a quantum fluctuation regime.
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ورودعنوان ژورنال:
- Physical review letters
دوره 88 7 شماره
صفحات -
تاریخ انتشار 2002