Li and Nb codoping in dielectric properties and phase transitions of KTaO3: Reentrant dipolar glass and long-range dipole ordering |
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| Authors: | V Trepakov M Savinov S Kappahn L Jastrabik P Camagni L A Boatner |
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| Institution: | 1. A.F. Ioffe Physical- Technical Institute , 194 021, St., Petersburg, Russia;2. Institute of Physics AS CR , 18121 Praha 8, Czech Republic;3. Institute of Physics AS CR , 18121 Praha 8, Czech Republic;4. FB Physik, University of Osnabrück , D-49069, Osnabrück, Germany;5. Dipartimento di Fisica “A. Volta” , Via Bassi 6, 27100, Pavia, Italy;6. Solid State Division, Oak Ridge Nat. Lab. , Oak Ridge, Tennessee, 37831, USA |
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| Abstract: | Abstract The highly polarizable perovskite-type oxide, KTaO3 doped simultaneously with Li+ and Nb5+ (K1?xLixTa1?yNbyO3, KLTN), reveals unexpected properties and ordering effects. Studies of the dielectric permittivity ?'(T, f) (10—300K, 100Hz-1 MHz) for x = 0.0014 and y = 0.024 show collective dipolar ordering effects with a transition from paraelectric into a mixed phase (coexisting dipole-glass-like and long-range ordered ferroelectric phases) taking place near 39 K. At 15 K another phase transition into a reentrant dipolar glass-like state is observed. Such a sequence of transitions and the existence of a reentrant glass state are unknown for electrical dipolar systems. |
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| Keywords: | Off-center impurity ions Phase transitions Dipole glass |
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