Single-domain state

In the single-domain state, many ferroelectric crystals also exhibit high optical nonlinearity and this, coupled with the large standing optical anisotropies (birefringences) that are often available, makes the ferroelectrics interesting candidates for phase-matched optical second harmonic generation (SHG). 

Both of these are considered to arise from the different orientation of fer-roelastic domains below Ta and local distortion due to multidomaining. The inset in Fig. 13a shows An for the (llO)c face measured under three conditions (i) no electrode, (ii) with sputtered Au, and (iii) with pasted Ag. These results imply that even the sputtered Au on the 7 x 0.3 mm side can affect multidomaining below Ta. These results suggest that attention must be paid to ensure the single-domain state below Ta. 

Under the size reduction of small magnetic particle a critical volume exists when the energy to produce a domain wall becomes higher than the external magnetostatic energy for the single-domain state. This critical size depends on type of magnetic material and is about few tens nanometers. For a spherical particle, this critical diameter could be estimated as [1] ... 

Surface screening of depolarization field makes the single-domain state of a particle to be energetically preferable. 

In addition, a reorientation of the Jahn-Teller domains occurs in the magnetic field, and at some critical mean field the sample reaches a single domain state (Cooke et al. 1972, Kazey and Sokolov 1986, Melcher et al. 1973). in TmVO is, apparently, equal to 70 kOe, because at this mean field the following condition is fulfilled phonons are scattered on the sample grain boundaries but not on the boundaries which separate the domains (fig. 100, dashed line). 

The near-vertical portions of the loop in Figure 8.5 correspond to the reversal of the spontaneous polarization when opposite 180°-domains nucleate and grow. The near-horizontal portions represent saturated single-domain states. The remanent polarization (E = 0) shown is about 0.27Cm , the coercitive field strength... 

Ferroelectric PBT1O3 From a Single-domain State to Composite Components... 

Pj- and Pj vectors (Figure 7) can be satisfied on poling the composite sample in an electric field E II 0X3 due to the significant difference between the coercive fields [1-4, 35] of SC and polymer. In case of the composite based on single-domain PbTiOs SC, a bias eleetric field Eh II 0X3 is applied to stabilize the single-domain state with Pj tt OX3 in each SC rod. 

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