In this study, the samples were prepared with mixed two colossal magnetoresistance materials and sintered at high temperature. Then analysis the affect of doping concentration in MR effect, and applied it on the magnetic thin film. X-ray diffraction images and SEM images were used to show the lattice structure and grain boundary. The RT curves show the position of Tp temperature ,and pH curves shows the characteristic of MR.

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The sample are prepared by co-sintering the pure 3D ferromagnetic colossal magnetoresistance La0.7Sr0.3MnO3 (113) and the 2D spin-glass magnetic insulator La0.7Sr0.3MnO3¡ESrO (214) with an ordered 2D magnetic-insulator superstructure. Increase the magnetic scattering and collision probabilities of the carries on the interface of the two kinds of CMR materials. The LFMR is enhanced by the electron scattering between these two phases. (La0.7Sr1.3MnO4)x / ( La0.7Sr0.3MnO3)1-x composites with x=0.1¡B0.15¡B0.2¡B0.3¡B0.5 have been fabricated by sintering the mixture of the pure La0.7Sr0.3MnO3 (n=¡Û) and the La0.7Sr1.3MnO4(n=1) at 1400 for 24 hours. Part of the 113 phase reacted with 214 phase during the 1400¢J annealing process and formed the antiferromagnetic phase , La1-2ySr2+2yMn2O7 (327), with the unknown content, y. The £l-H curve shows the magnetic interaction between the interface grain numbers of the 113 and 327 affects the effect of the low field magnetoresistance effect.

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The low-field magnetoresistance of colossal magnetic thin film can be enhanced by proton implantation. Compare with the as grown sample, the implantation samples has lower transition temperature and higher resistivity. By the hall measurement, we can get the carrier type and carrier concentration. The hall magnetoresistance (MRH) is much greater than the longitude magnetoresistance (MR). Chapter 1. Introduce experiment purpose and expected results. Chapter 2. Introduce the basic theorem of colossal magnetic materials. Chapter 3. The steps of experiment. Chapter 4. Results and discussion. Chapter 5. The conclusion.

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1,000 miles marks the culmination of my course of study at the University of Texas. As an MFA student in the playwriting program, I have juggled my responsibilities to the department with my role as a professional playwright, frequently splitting time between Austin and my hometown of Chicago, where I opened four world premieres from 2010-2012. In this thesis, I discuss the ways in which my work has been influenced by the aesthetics of both artistic communities. I focus on two of my plays in particular: Kingsville, which premiered in Chicago during my first semester at UT, and Colossal, which opened in Austin just weeks before graduation. Through the lens of these two plays, I outline my artistic evolution over the past three years, highlighting the ways in which my work has drawn from the very best of Chicago’s storefront theaters and Austin’s experimental scene. / text

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Abstract It is know that the crystal structure and the magnetic ordering in La1-xAxMnO3(A=Ca,Sr,Ba) may disrupted by introducing various defect. This disorder weakens the Hund coupling and, thus, the double-exchange interaction between Mn3+ and Mn4+. Combining with John-Teller distortion enhanced by the defects, the magnetoresistance (MR) effect is enhanced. Up to date, the generated defects were mostly columnar defects or chemical substitution defects. In this study we generated different type of defect, point defects, and inrestigate its effect on MR effect. La0.7Sr0.3MnO3 and La0.7A0.3MnO3 films were deposit on LaAiO3 (001) and SrTiO3 (001) substrates by pulse laser deposition technique. Films were patterned with a standard photolithography. Point defects were introduced by irradiated high (1.7 and 3MeV) and low (10KeV) energy protons. We found that, the low dose sample exhibits both conductivity and the low field MR enhancement. Which were believed due to introduce acceptor level and the magnetic structure defects. When the dose was high, the structure defects leaded strong scattering effect that lowed the conductivity. The MR in high dose sample was also enhanced near by transition temperature.