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Jiles, D C

Publications and source records attributed to Jiles, D C.

Growth and characterization of Pt-protected Gd{sub 5}Si{sub 4} thin films

Successful growth and characterization of thin films of giant magnetocaloric Gd{sub 5}(Si{sub x}Ge{sub 1−x}){sub 4} were reported in the literature with limited success. The inherent difficulty in producing this complex material makes it difficult to characterize all the phases present in the thin films of this material. Therefore, thin film of binary compound of Gd{sub 5}Si{sub 4} was deposited by pulsed laser deposition. It was then covered with platinum on the top of the film to protect against any oxidation when the film was exposed to ambient conditions. The average film thickness was measured to be approximately 350 nm using a scanning electron microscopy, and the composition of the film was analyzed using energy dispersive spectroscopy. X-ray diffraction analysis indicates the presence of Gd{sub 5}Si{sub 4} orthorhombic structure along with Gd{sub 5}Si{sub 3} secondary phase. The transition temperature of the film was determined from magnetic moment vs. temperature measurement. The transition temperature was between 320 and 345 K which is close to the transition temperature of the bulk material. Magnetic moment vs. magnetic field measurement confirmed that the film was ferromagnetic below 342 K.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Developments in deep brain stimulation using time dependent magnetic fields

The effect of head model complexity upon the strength of field in different brain regions for transcranial magnetic stimulation (TMS) has been investigated. Experimental measurements were used to verify the validity of magnetic field calculations and induced electric field calculations for three 3D human head models of varying complexity. Results show the inability for simplified head models to accurately determine the site of high fields that lead to neuronal stimulation and highlight the necessity for realistic head modeling for TMS applications.

36 MATERIALS SCIENCE↗

Effect of deviation from stoichiometric composition on structural and magnetic properties of cobalt ferrite, CoxFe3-xO4 (x = 0.2 to 1.0)

The effects of deviation from stoichiometric composition on the structural and magnetic properties of cobalt ferrite, Co{sub x}Fe{sub 3-x}O{sub 4} (x = 0.2 to 1.0), are presented. Both CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} have a spinel crystal structure, and it might be expected that intermediate compositions would have the same structure. However, results show that synthesis via the ceramic method leads to the development of a secondary {alpha}-Fe{sub 2}O{sub 3} phase. Both structural and magnetic properties are altered depending on the concentration of the {alpha}-Fe{sub 2}O{sub 3} phase. Saturation magnetization is at a maximum for the stoichiometric composition (i.e., x = 1.0) and thereafter decreases with x. In attempts to achieve the properties required for application, the ceramic method offers the ability to selectively adjust the concentrations of both CoFe{sub 2}O{sub 4} and {alpha}-Fe{sub 2}O{sub 3} phases.

36 MATERIALS SCIENCE↗