We will present results for tunable microwave devices based on a microstrip and co-planar waveguide geometries. These structures, prepared by sputtering on GaAs or Si substrates, are compatible in size and growth process with on-chip high-frequency electronics. We will discuss on-wafer notch filters, nonlinear devices such as signal to noise enhancers and nonreciprocal devices such as isolators. For the notch filters, we observed power attenuation up to 100 dB/cm and an insertion loss on the order of 2-3 dB for both Permalloy- and Fe-based structures. The operational frequency ranges from 5 to 35 GHz for external fields below 5 kOe. We discuss methods to increase operational frequency and reduce device linewidth. Using these techniques we are able, for example, to obtain an operational frequency of 11 GHz at zero applied field and to narrow the device linewidth from 3 GHz to 330 MHz. The operational frequency, which can be obtained from the ferromagnetic resonance condition, is set by material properties such as saturation magnetization, anisotropy fields, the gyromagnetic ratio, and the magnitude of an applied field . Thus, by using different materials and external fields we can create devices which function over a wide range of frequencies. A tunable microstrip signal-to-noise enhancer based on NiFe films operates due to the first- and second-order Suhl instability. The enhancement factor is 10 dB for a structure involving only the second order instability and an enhancement factor of 30 dB is found for a structure where the first order instability is allowed. We use Ni nanowires to build microwave isolators (non-reciprocal devices). The attenuation of the wave in forward and reverse direction shows a difference in transmission coefficients. The isolation is ~ 6 dB/cm at 23 GHz. The bandwidth of the device is relatively large (5-7 GHz) in comparison to ferrite-based devices.<-->

Dust is a critical component of galaxies. Without it, normal stars cannot form. And yet, our understanding of how dust is produced in the early Universe and what form it would take remains limited. Using the Infrared Spectrograph on the Spitzer Space Telescope, we have observed sources of dust in Galactic globular clusters and nearby dwarf galaxies, including systems with elemental abundances almost as primitive as the highest redshift objects yet observed. These samples probe the relation between the initial elemental abundances of a star and the quantity of dust it can inject into its environment before it dies. We have found that carbon stars can produce significant amounts of dust, even in the most primitive systems we have observed. The influence of carbon stars in the early Universe may be understated.

I will overview the GLIMPSE surveys of our Galactic Plane, done with the Spitzer Space Telescope over the last 6 years, and continuing on for the next 2 years. I will highlight some of the scientific results from the survey, and then go into more details about my area of interest, star formation. I will describe a program we have designed to determine the star formation rate of our Galaxy by producing a population synthesis model of forming stars and comparing to the GLIMPSE catalogs. This independent method can be compared to the standard Kennicutt-Schmidt law that is used on all the other galaxies in the universe.

High mass X-ray binaries that also produce very high energy radiation on the order of MeV-TeV (\x{03B3}-ray binaries) are a rare and interesting class of objects. Only five of these objects have been discovered to date, and I am currently involved in a multiwavelength study of two of these systems. I will present the latest orbital solution for LS 5039 and newly determined stellar parameters for HD 259440, the optical counterpart of HESS J0632+057.

Australian universities are experiencing declining enrollments in Physics and Astronomy courses. Senior high school students are not electing to study these subjects in their final two years of school. This project is a collaboration between the educational sector and two universities designed to investigate the impact of inquiry-based astronomy on redressing the increasingly negative attitudes of students as they progress through high school science. The use of the Faulkes Telescopes is designed as an engagement mechanism to allow students and their teachers to undertake real science investigations while addressing other key curriculum areas (engineering, mathematics, physics and technology).

Nonlinear spin waves in magnetic systems are of both fundamental and technological interest. This presentation will cover two topics on the chaotic excitation of nonlinear spin waves. One will be on the excitation of chaotic surface spin waves through four-wave modulational instability, and the other will be on the excitation of chaotic backward volume spin waves through three-wave nonlinear processes. The high order nonlinear Schrödinger equation predicts that the modulational instability of nonlinear waves could lead to the chaotic behaviors of the waves. Such chaotic excitations have been observed experimentally for the waves that have attractive nonlinearity. For the waves with repulsive nonlinearity, however, there have been no experimental observations so far. The first half of this talk will present our recent work on the excitation of chaotic surface spin waves through the four-wave modulational instability processes. The work was conducted in a magnetic film strip-based active feedback ring. The magnetic film/field configuration was set to allow for the propagation of surface spin waves that have repulsive nonlinearity. The self-generation of chaotic spin waves in the ring was observed. The chaotic nature of the signals was confirmed by irregular waveforms, broad spectra, and finite fractal dimensions. Previous work has demonstrated the three-wave interactions between the surface and backward volume spin waves as well as the excitation of chaotic spin waves through those interactions. In principle, the three-wave interactions of pure backward volume spin waves are also possible at low magnetic fields. In practice, these interactions have never been observed experimentally. The second half of this talk will present our recent experimental observation on the three-wave interactions of backward volume spin waves and the excitation of chaotic spin waves through the three-wave processes. As in the four-wave process experiments, the three-wave interaction experiments were also carried out with a feedback ring structure, and the chaotic natures of the signals were confirmed by the broad power-frequency spectra and the finite fractal dimensions. <-->

A few years ago several experimental breakthroughs created a new interdisciplinary field. It combines atomic physics with condensed matter physics, and promises to manufacture new states of matter with constituents which are custom-picked atoms whose interactions can be manipulated at will. Since then the field has witnessed a number of remarkable successes, such as creating an artificial high temperature superconductor, observing an artificially prepared superconductor-insulator transition, and creating an artificial magnet. At the same time, a number of far fetching predictions about the future successes in the field so far failed to materialize. I will discuss the achievements and setbacks of the field, and describe how future progress can only be achieved by combining the vision coming from condensed matter physics and realistic limitations imposed by atomic physics.