In situ observation of electric-field-induced domain switching and crack propagation in poled PMNT62/38 single crystals

Five types of ferroelectric domain walls (DWs) are present in Bi4Ti3O12 single crystals (Ye et al., 2015). Here their motion was investigated in situ using transmission electron microscopy and optical microscopy. The motion of P (a)-90° DWs, P (a)-180° DWs and P (c)-180° DWs was observed through electron beam poling in a transmission electron microscope. The growth of new P s(a)-180° nanodomains was frequently seen and they tended to nucleate at preexisting P s(a)-90° DWs. Irregularly curved P (c)-180° DWs exhibit the highest mobility, while migration over a short range occurs occasionally for faceted P s(a)-90° DWs. In addition, the motion of P s(a)-90° DWs and the growth/annihilation of new needle-like P s(a)-90° domains in a 20 µm-thick crystal were observed under an external electric field on an optical microscope. Most of the new needle-like P s(a)-90° domains nucleate at preexisting P s(a)-90° DWs and the former are much smaller than the latter. This is very similar to the situation for P s(a)-180° domain switching induced by electron beam poling in a transmission electron microscope. Our observations suggest the energy hierarchy for different domains of P s(c)-180° ≤ P s(a)-180° ≤ P s(a)-90° ≤ new needle-like P s(a)-90° in ferroelectric Bi4Ti3O12.

Download Full-text

Electric field-induced crack growth and domain-structure evolution for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3) O3–28%PbTiO3 ferroelectric single crystals

Journal of Materials Research ◽

10.1557/jmr.2008.0415 ◽

2008 ◽

Vol 23 (12) ◽

pp. 3387-3395 ◽

Cited By ~ 13

Author(s):

F. Fang ◽

W. Yang ◽

F.C. Zhang ◽

H. Qing

Keyword(s):

Electric Field ◽

Crack Propagation ◽

Single Crystal ◽

Single Crystals ◽

Crack Growth ◽

Domain Structure ◽

Boundary Structure ◽

Structure Evolution ◽

In Situ Observation ◽

Oriented Single Crystal

In situ observation of the electrically induced crack growth and domain-structure evolution is carried out for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3)O3–28% PbTiO3 (PMN–PT 72/28) ferroelectric single crystals under static (poling) and alternating electric fields. On the same poling electric field, domains are in the stable engineered domain state where four equivalent polarization variants coexist for [100]-oriented single crystal, while parallel lines representing the 71° domain boundaries appear for [101]-oriented one. Under the same cyclic electric field, the [100]-oriented single crystal shows much higher crack propagation resistance than that of a [101]-oriented crystal. Apart from the material aspects, such as crystallographic fracture anisotropy and non-180° domain boundary structure, crack boundary condition plays an important role in determining the crack propagation behavior.

Download Full-text

In Situ Observation of Fatigue Crack Growth and 90º Domain Switching for BaTiO3 Ferroelectric Single Crystal under Cyclic Electric Loading

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.33-37.145 ◽

2008 ◽

Vol 33-37 ◽

pp. 145-150

Author(s):

Fei Fang ◽

Fang Cheng Zhang ◽

Wei Yang

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Stress Field ◽

Electric Field ◽

Crack Growth ◽

Domain Switching ◽

Crack Tip ◽

In Situ Observation ◽

Alternating Electric Field

In-situ observation of the fatigue crack growth and 90o domain switching was carried out for BaTiO3 ferroelectric single crystals under alternating electric field. It is shown that during the electric cycling, the crack propagates continuously. Parallel lines of 90o domain boundaries can be seen and they flip at each reversal of the alternating electric field. The width of the 90o domain switching zone grows with the number of cycles and its frontal always lies ahead of the crack tip. It is suggested that the cyclic stress field induced by the repeated 90o domain switching at the crack tip, as well as the stress field caused by the electrically activated material between the electrode and the material under the electrodes contribute to the observed fatigue crack growth.

Download Full-text