Glassy domain wall matter in KH2PO4 crystal: Field-induced transition

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 T-f(omega, V), some 30K below the ferroelectric T-C; timescale tau(f)(T, V) exhibiting Vogel-Fulcher (VFT) divergence. Sharply distinct low-and high-field behaviors of T-C(V), DW-Tg(V), VFT-T-0(V), barrier energy U-a(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 (epsilon'poled > epsilon'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. (C) 2013 AIP Publishing LLC.