@article { ISI:000272052200068, title = {Enhanced nonvolatile resistive switching in dilutely cobalt doped TiO2}, journal = {Applied Physics Letters}, volume = {95}, number = {20}, year = {2009}, month = {NOV}, pages = {203502}, publisher = {AMER INST PHYSICS}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {

Incorporation of dilute concentration of dopant having a valence state different than that of the host cation enables controlled incorporation proximity vacancy defects for local charge balance. Since nonvolatile resistive switching is a phenomenon tied to such defects, it can be expected to be influenced by dilute doping. In this work, we demonstrate that enhanced nonvolatile resistive switching is realized in dilutely cobalt doped TiO2 films grown at room temperature. We provide essential characterizations and analyses. We suggest that the oxygen vacancies in the proximity of immobile dopants provide well distributed anchors for the development of systematic filamentary tracks.

}, keywords = {cobalt, Doping, magnetic switching, random-access storage, titanium compounds, vacancies (crystal), valency}, issn = {0003-6951}, doi = {10.1063/1.3263713}, author = {Bogle, Kashinath A. and Bachhav, Mukesh N. and Deo, Meenal S. and Valanoor, Nagarajan and Ogale, Satishchandra B.} } @article { ISI:000279514400059, title = {Nanoscale modulation of electronic states across unit cell steps on the surface of an epitaxial colossal magnetoresistance manganite film}, journal = {Applied Physics Letters}, volume = {96}, number = {26}, year = {2010}, month = {JUN}, pages = {Article No. 263108}, publisher = {AMER INST PHYSICS}, type = {Article}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {

The nature of electronic states near the edge of unit cell steps on the surface of epitaxial La(0.7)Sr(0.3)MnO(3) (LSMO) thin films grown by real-time reflection high energy electron diffraction monitored pulsed laser deposition is examined by scanning tunneling microscopy and scanning tunneling spectroscopy techniques. It is observed that the electronic states are strongly modulated near the step edge with considerably high gap at the edge and low gap on the terrace. This modulation weakens at low temperature. The temperature evolution of the density of states and the nature of gap in deep metallic state of LSMO are also discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3455886]

}, keywords = {colossal magnetoresistance, electronic density of states, lanthanum compounds, magnetic epitaxial layers, Nanostructured materials, pulsed laser deposition, reflection high energy electron diffraction, scanning tunnelling microscopy, scanning tunnelling spectroscopy, strontium compounds}, issn = {0003-6951}, doi = {10.1063/1.3455886}, author = {Rana, Abhimanyu and Bogle, Kashinath A. and Game, Onkar S. and Patil, Shankar and Valanoor, Nagarajan and Ogale, Satishchandra B.} } @article { ISI:000312301800017, title = {Epitaxial magnetic oxide nanocrystals via phase decomposition of bismuth perovskite precursors}, journal = {Advanced Functional Materials}, volume = {22}, number = {24}, year = {2012}, month = {DEC}, pages = {5224-5230}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The phase instability of bismuth perovskite (BiMO3), where M is a ferromagnetic cation, is exploited to create self-assembled magnetic oxide nanocrystal arrays on oxide supports. Conditions during pulsed laser deposition are tuned so as to induce complete breakdown of the perovskite precursor into bismuth oxide (Bi2O3) and metal oxide (M-Ox) pockets. Subsequent cooling in vacuum volatizes the Bi2O3 leaving behind an array of monodisperse nanocrystals. In situ reflective high energy electron diffraction beam is exploited to monitor the synthesis in real-time. Analysis of the patterns confirms the phase separation and volatization process. Successful synthesis of M-Ox, where M = Mn, Fe, Co, and Cr, is shown using this template-free facile approach. Detailed magnetic characterization of nanocrystals is carried out to reveal the functionalities such as magnetic anisotropy as well as larger than bulk moments, as expected in these oxide nanostructures.

}, keywords = {Bi2O3 evaporation, bismuth perovskites, epitaxial nanostructures, magnetic oxides, phase separation}, issn = {1616-301X}, doi = {10.1002/adfm.201201066}, author = {Bogle, Kashinath A. and Cheung, Jeffrey and Chen, Yong-Lun and Liao, Sheng-Chieh and Lai, Chih-Hung and Chu, Ying-Hao and Gregg, John M. and Ogale, Satishchandra B. and Valanoor, Nagarajan} } @article { ISI:000338011200013, title = {Scaling behavior of resistive switching in epitaxial bismuth ferrite heterostructures}, journal = {Advanced Functional Materials}, volume = {24}, number = {25}, year = {2014}, month = {JUL}, pages = {3962-3969}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Resistive switching (RS) of (001) epitaxial multiferroic BiFeO3/La0.67Sr0.33MnO3/SrTiO3 heterostructures is investigated for varying lengths scales in both the thickness and lateral directions. Macroscale current-voltage analyses in conjunction with local conduction atomic force microscopy (CAFM) reveal that whilst both the local and global resistive states are strongly driven by polarization direction, the type of conduction mechanism is different for each distinct thickness regime. Electrode-area dependent studies confirm the RS is dominated by an interface mechanism and not by filamentary formation. Furthermore, CAFM maps allow deconvolution of the roles played by domains and domain walls during the RS process. It is shown that the net polarization direction, and not domain walls, controls the conduction process. An interface mechanism based on barrier height and width alteration due to polarization reversal is proposed, and the role of electronic reconstruction at the interface is further investigated.

}, issn = {1616-301X}, doi = {10.1002/adfm.201400110}, author = {Rana, Abhimanyu and Lu, Haidong and Bogle, Kashinath A. and Zhang, Qi and Vasudevan, Rama and Thakare, Vishal and Gruverman, Alexei and Ogale, Satishchandra and Valanoor, Nagarajan} }