Electrodeposition Found as a Versatile Tool in the Preparation of Magnetic Nanostructures
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crystal growth. This assertion is supported by short ion-dipole distances in the product crystal, as well as the observation that the degree of polar order in the crystal varied directly with the magnitude of the dipole moment of the guest. The scientists said that the polar order of the bulk crystal cannot be the result of guest-to-guest interactions because of the large separation between the guests brought about by the host structure. The guest dipoles are further separated by the tilting of the BPDS pillars and guest dipoles relative to the crystallographic c-axis of the crystal. This tilting is the result of the distortion of guanidinium sheets during crystal growth to accommodate the guest molecules. The value of the tilt angle is the same for all pillars and guests in a single layer of the crystal, but is reversed in adjacent layers, which serves to further separate the guest dipoles. In addition to the physical separation of the guests, the charged guanidinium sheets also act as a dielectric screen for dipole-dipole interactions between guests in adjacent layers. Additional evidence for the absence of guest dipoledipole interactions comes from molecular modeling, which shows that guest dipoledipole interactions favor a different guestdipole configuration than the one observed in the product crystal. GREGORY KHITROV
Electrodeposition Found as a Versatile Tool in the Preparation of Magnetic Nanostructures In an effort to investigate the suitability of electrodeposition for the controlled preparation of high-quality structures on an atomic scale, Yukimi Jyoko of Fukui National College of Technology in Japan and Walther Schwarzacher of the University of Bristol studied the growth of magnetic Co/Pt and CoNi/Pt nanostructures, as reported in the August issue of Electrochemical and Solid-State Letters. The obtained multilayered nanostructures exhibit perpendicular magnetic anisotropy and a large magnetic coercivity. The codeposition of Ni, as well as the deposition overpotential, has a significant influence on the film properties.
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Magnetic multilayered nanostructures have received considerable attention since the discovery of perpendicular magnetic anisotropy, the magneto-optical Kerr effect, and giant magnetoresistance in metallic multilayers. New magnetic nanostructures have potential for application in high-density magneto-optical recording media or magnetoresistive sensor devices. “Most magnetic nanostructures have been fabricated by sputtering or molecularbeam epitaxy,” said Schwarzacher, lecturer of physics. “Electrodeposition, however, may be more promising for all practical purposes, given the efficiency and simplicity of the required equipment.” Recently, he and Jyoko’s group at Fukui proved that there i
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