Single domain configuration

For small particles, there is a critical diameter below which the creation of a domain wall results in a larger energy contribution (per volume unit) than the magnetostatic energy of a single domain configuration ... 

A tool to visualize the domains in thin films is the 3-D piezoresponse force microscope (pfm, see also Chapter 12). Figure 1.22 shows an epitaxial pzt thin films grown on a (001) single crystalline SrTiC>3 substrate coated with La0.5Sr0.5CoO3 oxide layer. A detailed analysis point out that a self-polarized polarization mechanism is observed because the out-of-plane polarization in c-domains are preferentially orientated towards the bottom electrode, i. e. a remanent polarization exists without applying an external field. The domain configuration is always of the head-to-tail type. 

The detailed geometry and dynamics of changes in domain configuration in a single crystal accompanying changes in applied field are complex and there is... 

The hysteresis loop of a ceramic varies according to composition and ceramic structure but is typically of the form shown in Fig. 2.46(b). The coercive field is higher and the remanent polarization is lower than for a single crystal. Changes in both 180° and 90° domain configurations take place during a cycle and are impeded by the defects and internal strains within the crystallites. 

Figure 1. Schematic of magnetic domain configuration for a) multi-domain and b) single domain ferromagnets.

Terms To and T describe unordered proton configurations in the bonds, so that the probability of single-domain chain oscillations becomes a+lV- 2 cos [(Ei — Eo)tjh. When To and Ti are small in comparison with the a terms, one can treat the chain repolarization as that of a single domain. Contribution of To and Ti in (442) becomes more appreciable at the increasing of the integral J that leads to the destroying the correlated proton dynamics. For example, in the case of a chain consisting only of two bonds, which is characterized by periodical boundary conditions, we have... 

Several magnetization isotherms for temperatures between 4.2 and 106.4 K are shown in fig. 6.16. With an applied field along [100], observation of the appropriate neutron diffraction satellites indicated the gradual formation of a single domain, with the field normal to the plane of the spiral, that is completed by about 0.8 T. In such a configuration the magnetization arises from a lifting of the ordered moments out of the plane and, in the absence of anisotropy, the... 

Fig. 6.43. The magnetoresistance of gadolinium at 205 K, showing the spontaneous anisotropy described in section 6.1 and the linear negative magnetoresistance discussed in section 6.2. The arrows indicate the applied field needed to create a single domain in the two configurations (after McEwen and Webber 1976).

Wada S, Park SE, Cross LE, Shrout TR (1999) Engineered domain configuration in rhombohedral PZN-PT single crystals and their ferroelectric related properties. Eerroelectrics 221 147-155 Wallnofer W, Stadler J, Krempl P (1993) Temperature dependence of elastic constants of GaP04 and its influence on BAW and SAW devices. Proceedings of 7th European frequency and time forum, pp 653-657... 

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