In situobservation of thermally activated domain memory and polarization memory in an aged K⁺-doped (Ba, Sr)TiO₃single crystal

Abstract

Different ferroelectric domains are degenerate states of the same ferroelectric phase; thus they are energetically equivalent and, in principle there exists no preference for a particular domain pattern. However, the existence of point defects is considered to stabilize certain preferential domain states. In order to study the temperature violation on such stabilized domains, we performed in situ observation on an aged K⁺-doped (Ba, Sr)TiO₃ single crystal and found that both the domain configuration and polarization state can be memorized after experiencing a thermally activated ferro-para-ferro transition cycle, as manifested by a reappearance of the same domain pattern and double P-E hysteresis loop. In contrast, after the sample was aged in the paraelectric state (>10 min), these memory effects disappeared. The above memory effects are considered to originate from the interaction between point defects and the crystal symmetry driven by a symmetry-conforming tendency of point defects. Such a mechanism suggests that the memory effects are relevant to the existence of acceptor dopant and associated mobile oxygen vacancies, and they are not restricted to a particular dopant. Thus similar memory effects are expected to exist in a wide range of ferroelectric materials with acceptor doping.

Aging and deaging effects in shape memory alloys

“…5(b3)) so as to make the internal stress field ρ conform to the martensite crystallographic orientation everywhere, as a consequence of coupling between 2 e and ρ . Such "domain-pattern memory" induced by martensite aging has also been found experimentally in a Au-Cd martensitic alloy 13 and (Ba,Sr)TiO 3 ferroelectric single crystal 36 by optical microscopy. The macroscopic manifestation of this mesoscopic memory is the memory of the shape of previous martensitic alloy, i.e.…”

Aging-induced domain memory in acceptor-doped perovskite ferroelectrics associated with ferroelectric-ferroelectric transition cycle

“…In the following, we shall explain the origin of our reported aging-induced domain memory effect from the evolution of crystal symmetries and defect configurations/defect symmetries during the phase transition cycle. Aging manifests itself as a stabilization of domain states by the migration of point defects with time [10,[20][21][22][23]. The acceptor dopant produces oxygen vacancies in the system.…”

Enhanced energy storage density by reversible domain switching in acceptor doped ferroelectrics

“…The above terms are the traditional Ginzburg-Landau free energy. The G ρ is the contribution associated with ferroelectric aging, which we assume to be a double-well potential similar with that of the order parameter P. The reason is that the point defect distribution symmetry follows the symmetry of the ferroelectric phase and consequently the defect polarization P D aligns along the direction of the order parameter P. [16][17][18]25 The G ρ is given by,…”

“…15 These V •• O are mobile and can be redistributed over a long period after sudden disturbance such as the structural phase transition, or the domain reconfiguration. [16][17][18] In the equilibrium ferroelectric state (i.e. after aging in ferroelectric state for a long time), the polar crystal symmetry of ferroelectric phase will lead a polar distribution of V •• O .…”