Effect of oxygen concentration on the structural and magnetic properties of LaRh1/2Mn1/2O3 thin films

Epitaxial LaRh1/2Mn1/2O3 thin films have been grown on (001)-oriented LaAlO3 and SrTiO3 substrates using pulsed laser deposition. The optimized thin film samples are semiconducting and ferromagnetic with a Curie temperature close to 100 K, a coercive field of 1200 Oe, and a saturation magnetization of 1.7muB per formula unit. The surface texture, structural, electrical, and magnetic properties of the LaRh1/2Mn1/2O3 films was examined as a function of the oxygen concentration during deposition. While an elevated oxygen concentration yields thin films with optimal magnetic properties, slightly lower oxygen concentrations result in films with improved texture and crystallinity

Pseudo Linear Hall Effect Thruster Characterization through Potential, Magnetic, and Optical Measurements

Electric propulsion systems are a more mass efficient method for providing a change in velocity, ΔV, to on-orbit spacecraft, than their chemical counterparts. In comparison, electric systems generally have a much higher specific impulse, Isp, than chemical systems. One option within the realm of electric propulsion is Hall Effect Thrusters, which have moderately high specific impulse values. From their advent in the 1960s, Hall Effect Thrusters have been used for orbit station keeping, attitude control, and orbit transfer. Although the discharge cavity is conventionally circular, pseudo-linear or racetrack shaped cavities have been developed. Even though Hall thrusters have decades of flight heritage, there are still many plasma behavioral characteristics which are still unknown. Multiple non-intrusive measurement techniques were used to investigate plasma behavior both in the plume and in the channel of a pseudo linear Hall thruster. Through the visible emissions captured by a high-speed camera, breathing mode characteristics were induced and analyzed. Spoke structures were observed in only certain parts of the thruster channel. Additionally, the plume divergence was characterized by use of a Faraday probe along two axes of the thruster, indicating significantly different “keep out” regions for potential thruster use on spacecraft. Also, an irregularity was observed in the channel of the pseudo-linear thruster, which potentially could affect the lifespan of the thruster

A surface magnetic survey of Coshocton County, Ohio

A total field magnetometer survey of nine quadrangles in Coshocton County is presented. The survey area is bounded by 40.125 and 40.500 degrees latitude and -81.617 and -82.000 degrees longitude. The anomaly field is derived from the total field values that are corrected for the IGRF and the diurnal fields. Corrected residual values are machine gridded at one half mile spacings, corresponding to 52 rows (latitude) and 43 columns (longitude). The grid node values were then machine contoured to produce anomaly maps of the area. Two qualitative interpretations of the anomalies are given; 1.) Observed variations are due to basement faulting, or 2.) Observed variations are due to susceptibility and remanence variations across lithologic units.No embarg