Blue – as-prepared sample Red - annealed sample

1. Enhancement of Photoinduced Effects in Annealed Bi1-xCa xMnO3 thin filmsVera N. Smolyaninova, Towson University, DMR 0348939 • Doped rare-earth manganese oxides (manganites) exhibit a wide variety of fascinating properties and phenomena. A photoinduced insulator-to-conductor transition in charge-ordered manganites is especially interesting from the point of view of creating photonic devices. We studied the effects of annealing of manganite materials in order to better understand nature of photoinduced effects in manganites. We found that: • Photoinduced changes in annealed film are significantly larger than in as-prepared film. • The life time of the photoinduced changes are much larger in annealed films (up to 30 times at low temperatures). • Probable origin of photoinduced effect enhancement is trapping of electrons by oxygen vacancies, which introduces more charge carriers and weakens the charge ordering. • Increased magnitude of the photoinduced changes (and hence the optical contrast between insulating and photoinduced conducting phases) and their increased life time are desirable for potential photonic device applications, and for potential applications in opto-electronic switches. Temperature dependence of resistivity of BCMO annealed and as-prepared thin films with (dotted lines) and without laser light illumination (solid lines). The inset shows the current-voltage contact configuration Blue – as-prepared sample Red - annealed sample The lifetime of the photoinduced conducting phase as function of temperature

2. Undergraduate Education and STEM activitiesVera N. Smolyaninova, Towson University, DMR 0348939 Towson University is an undergraduate institution with strong emphases on undergraduate research. Three Towson students, Khim Karki, Benjamin Hofmann, and Jeffrey Demers, were involved in this research. Khim Karki presented his research at Society of Physics Students zone meeting, National Conference on Undergraduate Research, American Association of Physics Teachers meeting, American Physical Society March Meeting, and to the state legislators at University System of Maryland Annapolis Student Research Day. The PI made a presentation at Saturday Morning Science Series organized by Hackerman Academy at Towson University in order to attract more students into STEM (Science, Technology, Engineering, and Mathematics). This event attracted more than 300 attendees and was advertised in Washington Post. In her efforts to attract women in science, the PI organized whole day field trips for Mercy High School students (all girls), which has become annual tradition. She also conducted a Workshop at Sally Ride Science Festival at Towson (May 2008) for middle school girls.  Please insert an image or group of images here to illustrate your broader impacts activities. If you need more space, you may reduce the adjacent textbox. Please use lettering that is clearly visible (i.e. not too small). Please include a brief figure caption. Saturday Morning Science Series Mercy High School students at Towson