Ultrasonic Investigations of Tunnel States in KTaO<sub>3</sub>:Na
P. Doussineau; S. Ziolkiewicz; U. T. Höchli; P. Doussineau; Laboratoire d'Ultrasons, Université Pierre et Marie Curie, Tour 13, 4 Place Jussieu, 75252 Paris Cedex 05, France; S. Ziolkiewicz; Laboratoire d'Ultrasons, Université Pierre et Marie Curie, Tour 13, 4 Place Jussieu, 75252 Paris Cedex 05, France; U. T. Höchli; Laboratoire d'Ultrasons, Université Pierre et Marie Curie, Tour 13, 4 Place Jussieu, 75252 Paris Cedex 05, France
Журнал:
EPL (Europhysics Letters)
Дата:
1989-07-15
Аннотация:
Ultrasonic velocity and attenuation data are presented at T < 1 K for pure KTaO<sub>3</sub> and for KTaO<sub>3</sub>:X where X = Na and Li. Evidence is obtained for coherent tunnelling of Na ions within a correlation volume containing many impurities through barriers with distributed height and asymmetry parameters. Tunnelling is correlated with dipole-glass formation. No evidence of tunnelling is found in KTaO<sub>3</sub> and KTaO<sub>3</sub>:Li.
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