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Selected Works

Shi Xue Dou

2013

Films

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Inhomogeneities In Yba 2cu 3o 7 Thin Films With Reduced Thickness, O V. Shcherbakova, A V. Pan, S K. Gorman, S A. Fedoseev, I A. Golovchanskiy, S. X. Dou Jun 2013

Inhomogeneities In Yba 2cu 3o 7 Thin Films With Reduced Thickness, O V. Shcherbakova, A V. Pan, S K. Gorman, S A. Fedoseev, I A. Golovchanskiy, S. X. Dou

Shi Xue Dou

Morphology and physical properties of mono- (YBa2Cu3O7) and multilayered (YBa2Cu3O7/SmBa2Cu3O7/ YBa2Cu3O7) superconducting thin films with thickness ranging from 90 nm to 28 nm have been investigated. For both types of samples, the superconducting properties degraded with reduction of film thickness. Structural and electromagnetic properties were visualized through scanning electron microscopy and magneto-optical imaging, respectively, and revealed high level of inhomogeneity for thinner (<58 >nm) samples. However, samples with thickness above 58 nm showed enhanced homogeneity, which …


La And Nb Codoped Bifeo3 Multiferroic Thin Films On Lanio3/Si And Iro2/Si Substrates, Zhenxiang Cheng, Xiaolin Wang, Hideo Kimura, Kiyoshi Ozawa, S X. Dou Jun 2013

La And Nb Codoped Bifeo3 Multiferroic Thin Films On Lanio3/Si And Iro2/Si Substrates, Zhenxiang Cheng, Xiaolin Wang, Hideo Kimura, Kiyoshi Ozawa, S X. Dou

Shi Xue Dou

Nb and La codoped BiFeO3 thin films were fabricated on oxide bottom electrodes, LaNiO3/Si and IrO2/Si, by pulsed laser deposition method. The doped BiFeO3 thin film capacitor on LaNiO3showed a remnant polarization of more than 75 µC/cm2 in a saturated hysteresis loop. The same La and Nb codoped BiFeO3 thin film capacitors on IrO2 showed a larger remnant polarization, while with a significant contribution from the leakage current. Furthermore, the doped BiFeO3 capacitor on the LaNiO3 bottom electrode showed worse fatigue resistance than the film on IrO2. All the doped BiFeO3 thin films showed weak ferromagnetism at room temperature.


Improved Ferroelectric Properties In Multiferroic Bifeo3 Thin Films Through La And Nb Codoping, Zhenxiang Cheng, Xiaolin Wang, S X. Dou, Hideo Kimura, Kiyoshi Ozawa Jun 2013

Improved Ferroelectric Properties In Multiferroic Bifeo3 Thin Films Through La And Nb Codoping, Zhenxiang Cheng, Xiaolin Wang, S X. Dou, Hideo Kimura, Kiyoshi Ozawa

Shi Xue Dou

We report the significant improvement of the ferroelectric properties of BiFeO3thin film through control of electrical leakage by Nb doping. A very large remanent electrical polarization value of 80 µC/cm2 was observed in Bi0.8La0.2Nb0.01Fe0.99O3 thin film on Pt/Ti/SiO2/Si substrate. The doping effect of Nb in reducing the movable charge density due to oxygen vacancies in BiFeO3 was confirmed by the dielectric measurements. A very small loss was observed in the Nb and La codoped BiFeO3 thin film. As well as the improvement in the ferroelectric properties, the magnetic moment was also enhanced due to the doping of La.


Kinetic Roughening Of Magnetic Flux Penetration In Mgb2 Thin Films, Andrea Lucarelli, Stephanie Hummert, Andrea Chaney, Gunter Lupke, Brian Moeckly, Yue Zhao, S X. Dou Jun 2013

Kinetic Roughening Of Magnetic Flux Penetration In Mgb2 Thin Films, Andrea Lucarelli, Stephanie Hummert, Andrea Chaney, Gunter Lupke, Brian Moeckly, Yue Zhao, S X. Dou

Shi Xue Dou

Time-resolved magneto-optical studies are performed on MgB2 thin film samples grown by in situ pulsed laser deposition and in situ reactive deposition technique. The latter reveal dendritic avalanche-free flux penetration. The kinetic roughening of magnetic flux penetration is studied for applied ac current. Dynamic scaling laws determined for both static field and ac current are consistent with the directed percolation depinning model, placing the vortex dynamics in MgB2 in the same universality class as YBCO and Nb.