R. E. Camley

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Nonlinear effects in magnetic films are a subject of growing interest. The onset of parametric instability translates into practical power limits for microwave devices. Nearly all high-power studies were done in ferrites; recently, An investigated Permalloy. However, no work has been performed on planar devices or on iron films. Here, we investigate the(More)
We present here the application of an exchange spring multilayer system in an on-chip microwave device. The microwave devices were made in a coplanar geometry using a [SmCo/NiFe]<sub>10</sub> sputtered multilayer structure as the active material. At low fields we find an up shift of the operational frequency by more than 15 GHz for the multilayer system(More)
We study the focusing of bulk and surface spin waves in thin Yttrium iron garnet (YIG) films by solving the implicit dispersion relation obtained from the magnetostatic Maxwell equations. We then obtain constant frequency curves in k-space for the bulk and the surface modes. The focusing pattern is obtained from the slowness surface by finding the normal to(More)
The magnetic properties of arrays of one-dimensional nickel nano-wires with high aspect ratio have been studied by a network analyzer based ferromagnetic resonance (NA-FMR) technique using a flip-chip method in frequency domain. The frequency-field data [<i>fr</i>(<i>H</i> <sub>0</sub>)] is observed to be tunable up to 14-16 GHz with an applied field(More)
Magnetic resonance imaging is an important technique for identifying different types of tissues in a body or spatial information about composite materials. Because temperature is a fundamental parameter reflecting the biological status of the body and individual tissues, it would be helpful to have temperature maps superimposed on spatial maps. Here we show(More)
Recently, various groups have proposed competing relaxation mechanisms on the magnetization damping in thin magnetic films. We used the ferromagnetic resonance (FMR) technique to understand this behavior from FMR linewidths of sputtered thin Fe films sandwiched by normal metals (NM=Cu, Al, Ti, and Ta) of 30 Aring on each side. We made samples of(More)
Using the time evolution of the dynamic magnetization, we study the frequencies of spin excitations in small ferromagnetic bars with particular attention to the uniform mode. The calculation is done using micromagnetics, and the frequency of various modes is found as a function of the cell size used in the calculation. We find that the uniform mode and some(More)
In this paper, we designed, fabricated, and characterized a novel band-pass filter using ferrite nanoparticles as the active element in microstrip geometry. Two 50-Omega Cu transmitting/receiving antennas (one side fed and the other side shorted) were fabricated by photolithography on top of a thick layer of ferrites (Fe<sub>3</sub>O<sub>4</sub>)(More)
This paper describes a new, on-wafer microwave devices based on high magnetization, metallic ferromagnets such as Fe and Permalloy. These devices are small and could be integrated with high frequency electronics. Reduction of device dimensions in these monolithic microwave integrated circuits is important from the cost and reliability point of view. We(More)