Unanticipated Consequences of Reforms in School Governance

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Growth and Investigation of p−La2//3Ca1//3MnO3p-La_{2//3}Ca_{1//3}MnO_3/n-Si Heterostructures

We report the fabrication and investigation of p-n diode structures based on thin hole-doped $La_{2//3}Ca_{1//3}MnO_3$ films grown on n-type silicon substrates. $La_{2//3}Ca_{1//3}MnO_3$ films with typical thickness of about 400 nm were prepared using pulsed laser deposition. Reflection high-energy electron diffraction measurements revealed polycrystalline quality of $La_{2//3}Ca_{1//3}MnO_3$ thin films on Si substrates. The surface roughness of $La_{2//3}Ca_{1//3}MnO_3$ films investigated by atomic force microscopy was found to be in the range of 25÷30 nm. Studies of electrical properties showed that $La_{2//3}Ca_{1//3}MnO_3$/Si heterostructures exhibit nonlinear asymmetric I-V characteristics both at room temperature and at 78 K. Furthemore, it was shown that these I-V dependences are sensitive to magnetic field, especially at lower voltages

Viešojo administravimo teorijos: vadovėli

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Recent Advances in Synthesis of P-BH3 Compounds

International audienceThis chapter is dedicated to the main achievements since 2007 regarding the synthesis of BH3-phosphorus complexes. Among this class of compounds, phosphine-boranes are the most studied derivatives, mainly as valuable surrogates of phosphines, enabling easy handling and purification. Contrarily, metal phosphido-boranes were so far only considered as in situ intermediates in the P-functionalization of secondary phosphine-boranes. Thorough investigations of their structures as well as their chemical properties have been recently reported. Besides, phosphine-boranes and their phosphides, new families of phosphorus-BH3 complexes, have emerged as useful precursors of new structures in the asymmetric series. New routes toward optically active phosphinous-acid boranes and their esters were developed and applied to the synthesis of enantiopure P-stereogenic secondary and tertiary phosphine-boranes. The stereoselective synthesis of P-stereogenic aminophosphine-boranes, precursors of a new class of chiral ligands has been shortly reported. Studies dealing with the synthesis and reactivity of phosphonite-boranes were successfully applied to the development of efficient syntheses of functionalized H-phosphinates, compounds difficult to access by other routes