Domain wall thickness

Several studies have examined the thickness of the domain wall in ferroelectric materials [17]. The 90° a-c domain wall thickness has been measured using a transmission electron microscope (tem), [14] but distinguishing the positive and negative domains in 180° opposite polarization areas is difficult because these methods are used to observe the strain of arrangements of molecules. Direct clarification of the domain wall thickness is important with respect to both scientific and engineering aspects. 

Compared to domain-wall thicknesses, the determination of domain sizes tends to be very complicated [13, 14, 51, 93, 99-101], This is because domains are caused by the strongly geometry- and size-dependent magnetostatic selfinteraction. An exception is the critical single-domain radius... 

In nanocomposites, exchange coupling occurs between hard and soft magnetic nanograins. The hard phase provides coercivity and the soft phase contributes to magnetisation enhancement (see section 4.3). The grain size of both phases must be of the order of the hard phase domain wall thickness. The crystallisation behaviour plays an important role in the microstructural control of the magnetic properties. 

The original magnetic properties of hard nanostructures, described in the above sections, are direct consequences of the crystallite particle size reduction, when this size approaches the domain wall thickness, S. In this section, we apply and extend the findings of Chapters 3 and 4 to hard-magnetic nanostructures. We discuss (i) systems of exchange decoupled particles, and (ii) systems of exchange-coupled particles, themselves divided into single-phase systems and nanocomposites. 

The profile Bz(x, y) is determined by the ratio of two length scales thickness of a ferromagnetic film D and distance between the domain walls w (hereafter we consider the width of the domain wall to be much less than ). Provided the ferromagnetic film is rather thick (D w), the magnetic... 

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