Induced phase transitions in ferroelectrics with diffuse phase transition

Abstract

Dielectric, thermal, electrocaloric, elastic, optical, and electromechanical properties of three ferroelectrics with diffuse phase transition (PLZT 8/65/35 ceramics, lead magnesium niobate and strontium barium niobate single crystals) me investigated in dependence on temperature and electric field strength. It is shown that a polar phase can be induced by a n electric field within the nonpolar phase and vice versa, depending on whether the temperature is above or below Tb < T , . Analogies to stress-induced martensic transformations are emphasized. Dielektrische, thermische, elektrokalorische, elastische, optische und elektromechanische Eigenschaften von drei Ferroelektrika mit diffuser Phasenumwandlung (PLZT 8/65/35-Keramik, Bleimagnesiumniobat-und Strontiumbariumniobat-Einkristalle) werden in Abhingigkeit von der Temperatur und der elektrischen Feldstarke untersucht. Es wird gezeigt, daB sich eine polare Phase durch ein elektrisches Feld innerhalb der unpolaren induzieren laDt und umgekehrt eine unpolare in einer polaren, je nachdem ob die Temperatur ober-oder unterhalb T t < TC liegt. Auf Analogien zu spannungsinduzierten martensitischen Transformationen wird hingewiesen.

Nanoscale phase quantification in lead-free(Bi1/2Na1/2)TiO3−BaTiOGroszewicz1, Breitzke2, Dittmer3 et al. 2014Phys. Rev. B581340View full textAdd to dashboardCite

“…Relaxor ferroelectrics have been intensively studied in the past 30 years because of their intriguing structural and dielectric features [1][2][3]. Despite that, the nature of their ground state remains an open question [4][5][6][7][8][9][10][11][12]. Several models have been proposed to describe this puzzling class of materials [1,[5][6][7][8]13], two of which are mainly concerned with the structure of the ground state of relaxors [4].…”

“…Despite that, the nature of their ground state remains an open question [4][5][6][7][8][9][10][11][12]. Several models have been proposed to describe this puzzling class of materials [1,[5][6][7][8]13], two of which are mainly concerned with the structure of the ground state of relaxors [4].The random field (RF) model proposes a single-phase structure broken up into ferroelectric nanodomains. These nanodomains are kept small under the constraint of quenched random electric fields which originate from chemical disorder [7,14].…”

“…This state features macroscopic polarization and breaking of the cubic average symmetry [5,11,[15][16][17]. While the RF model suggests that this transformation and the formation of macroscopic ferroelectric domains are caused only by reorientation of previously nanometric ferroelectric domains, an additional mechanism is required when PNRs are considered.…”

Kinetics and thermodynamics of the ferroelectric transitions in PbMg1/3Nb2/3O3 and PbMg1/3Nb2/3O3-12% PbTiO3 crystals

“…In field-cooling (FC) at sufficient jEj a transition to the FE state is found, with the transition being abrupt in some crystalline samples lacking visible defects. [3][4][5][6][7] The same transition can also be reached by applying E after zero-field cooling (ZFC). Over a broad range of temperature (T), reducing E to zero leaves the material in a FE state.…”

“…[3][4][5][6][7] Even in the FE state, a substantial fraction of the material can remain disordered, with FE nanoregions imbedded in a more disordered glassy matrix, 8,9 as expected theoretically for similar materials. 10 In PMN-12%PT a FE state has been shown to be more stable than the unpolarized state below a transition temperature even when the electric field E ¼ 0, but results on the phase stability in pure PMN were less definite.…”