Full text loading...
Contrasting hysteresis loops of as-grown and annealed ( , ) single crystals. (a1) , (b1) , and (c1) show their hysteresis loops before aging; (a2) , (b2) , and (c2) show their hysteresis loops after aging at for .
Dielectric aging behavior of as-grown and annealed ( , ) single crystals. is the dielectric permittivity of unaged sample and is the dielectric permittivity at (aging time). is a measure of relative change of permittivity.
Impurity ( and ) content of KF-grown single crystal as a function of annealing time at . The point at 0, 5, and represents the as-grown and annealed ( , ) samples, respectively.
Microscopic mechanism of the aging effect in single crystals associated with defect complexes (a) , (b) , and (c) , respectively. (a1), (b1), and (c1): equilibrium paraelectric state; (a2), (b2), and (c2): unaged ferroelectric state; (a3), (b3), and (c3): ferroelectric state after aged; and (a4), (b4), and (c4): the ferroelectric state after a domain switching by an electric field. is the conditional probability of finding an oxygen vacancy at sites (1–12) around a given acceptor at site 0. is the conditional probability of finding ions at sites (1–12) around a given acceptor or vacancy at site 0. The defect symmetry is defined by the symmetry of the or , as shown in the figures. Large squares/rectangles represent crystal symmetry and small squares/rectangles represent defect symmetry.
Article metrics loading...