Glassy Domain Wall Matter in KH2PO4 Crystal: Field-Induced Transition
arXiv:1302.6078 · doi:10.1063/1.4821919
Abstract
We have investigated the domain wall (DW) dielectric response of potassium dihydrogen phosphate (KH2PO4) crystal under 0-500V dc-bias electric field. Activated DW-contribution onsets freezing at Tf(ω, V), some 27K below the ferroelectric TC; timescale τf(T, V) exhibiting Vogel-Fulcher (VFT) divergence. Sharply distinct low- and high-field behaviors of TC(V), DW-Tg(V), VFT-T0(V), barrier energy Ua(V), and DW glass-fragility m(V) signify a field-induced transition from randomly-pinned/vitreous to clustered/glass-ceramic phases of domain wall matter. Field-hysteresis (ε'poled > ε'unpoled) observed at high dc-bias indicates coexistent unclustered DW phase, quenched-in during the field-cooling. We construct a paradigm T-E phase diagram depicting the complex glassy patterns of domain wall matter.
16 pages, 5 figures, 28 references