Oxygen vacancy migration and time-dependent leakage current behavior of Ba0.3Sr0.7TiO3 thin films

The leakage current response of high-permittivity columnar-grown (Ba,Sr)TiO3 thin films has been studied at elevated temperatures under dc load. We observe a thermally activated current prior to the onset of the resistance degradation with an activation energy of E-A=1.1 eV. A point defect model is applied to calculate the migration of electronic and ionic defects under the dc field as well as the current response of the system. We find that the peak in current is not caused by a space-charge-limited transient of oxygen vacancies, but related to a modulation of the electronic conductivity upon oxygen vacancy redistribution. Furthermore, we show that after the redistribution of electronic and ionic defects, no further increase in conductivity takes place in the simulation. (C) 2005 American Institute of Physics

A comparative study of phage PR4 susceptibility of IncP and IncN plasmid containing bacterial strains

Thesis (B.S.) in Microbiology -- University of Illinois at Urbana-Champaign, 1990.Includes bibliographical references (leaves 13-14)Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1990]. 1 microfiche (24 frames): negative.s 1990 ilu n