Scanning Hall microscope

Using a scanning Hall microscope, a stripe-shaped domain structure has been observed in a (Ga.Mn)As sample with tensile strain and perpendicular easy axis (Shono et al. 2000 Fukumura et al. 2001). The Baukhausen noise due to the scattering from the domain wall movement has also been observed in magnetotransport measurements (Hayashi et al. 2000). 

The study of these systems have become possible thanks to the development of various preparation routes, from sophisticated routes for the preparation of model materials with controlled nanostructures to industrial routes for the production of large quantity of materials. It has benefited as well from the development of new experimental techniques, allowing the properties of matter to be quantitatively examined at the nanometre scale. These include Hall micro-probe [3] or micro-SQUID magnetometry [4], XMCD at synchrotron radiation facilities [5] and scanning probe microscopes [6]. This is not the topic of this chapter to describe in detail these various techniques. They are only quoted in the following sections. The reader may find in the associated references the detailed technical descriptions that he may need. 

Hall and Williams reported that some of their films were made up of singlecrystal platelets parallel to the surface of the substrate and having areas of approximately 1000 nm and a thickness of 100 nm (film thickness) [95, 96]. This was determined by the use of both a polarizing microscope and by a scanning electron microscope. The structure of thicker films, produced by multiple evaporations of Pb and conversions to Pb(N2)3, such as used for the far-infrared work, was not reported [95,96,120]. However, the thick films were homogeneous as detected by Rutherford back-scattering of protons [128]. There is also evidence that the disorder was variable from film to film because of variations in the resolution at room temperature of the maximum in the optical extinction at 375 nm [95, 96, 122, 129]. As discussed above, this maximum is sensitive to irradiation, doping, and heat treatment. The resolution of this peak and the associated imperfections in the film are also apparently dependent on the details of the preparation techniques. 

Other researchers helped further electron microscopy technology. Ladislaus L. Marton of Brussels assembled the first micrograph of a biological sample, while Manfred von Ardenne of Berlin constructed the first scanning electron microscope in Berlin in 1937. At the University of Toronto, Cecil Hall, Albert Prebus, and James Hillier built a model of the... 

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