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Full-Text Articles in Physical Sciences and Mathematics

Dynamic Magneto-Optical Imaging Of Superconducting Thin Films, Frederick Wells, Alexey V. Pan, Stephen Wilson, Igor Golovchanskiy, Sergey Fedoseev, Anatoly B. Rosenfeld Jan 2016

Dynamic Magneto-Optical Imaging Of Superconducting Thin Films, Frederick Wells, Alexey V. Pan, Stephen Wilson, Igor Golovchanskiy, Sergey Fedoseev, Anatoly B. Rosenfeld

Australian Institute for Innovative Materials - Papers

We present a novel method for analysis of superconducting thin films using dynamic magneto-optical imaging, revealing hallmarks of flux penetration with temporal resolution around 1 ms (in the present work) or better. This method involves investigation of transient field and dynamic current distributions, which are calculated by an inversion procedure on the Biot-Savart Law, which we show to be valid under dynamic conditions. We compare and discuss the flux front penetration speed and evolution of current distribution in high quality YBa2Cu3O${}_{7-\delta }$ thin films with that of samples deliberately damaged in such a way as to reduce critical current density …


Tuning Superconductivity In Fese Thin Films Via Magnesium Doping, Wenbin Qiu, Zongqing Ma, Yongchang Liu, Md Shahriar Hossain, Xiaolin Wang, Chuanbing Cai, S X. Dou Jan 2016

Tuning Superconductivity In Fese Thin Films Via Magnesium Doping, Wenbin Qiu, Zongqing Ma, Yongchang Liu, Md Shahriar Hossain, Xiaolin Wang, Chuanbing Cai, S X. Dou

Australian Institute for Innovative Materials - Papers

In contrast to its bulk crystal, the FeSe thin film or layer exhibits better superconductivity performance, which recently attracted much interest in its fundamental research as well as in potential applications around the world. In the present work, tuning superconductivity in FeSe thin films was achieved by magnesium-doping technique. Tc is significantly enhanced from 10.7 K in pure FeSe films to 13.4 K in optimized Mg-doped ones, which is approximately 1.5 times higher than that of bulk crystals. This is the first time achieving the enhancement of superconducting transition temperature in FeSe thin films with practical thickness (120 nm) via …


Strain-Induced Magnetic Phase Transition In Srcoo3−Δ Thin Films, S J. Callori, S Hu, Joel Bertinshaw, Zhilian Yue, S Danilkin, Xiaolin Wang, V Nagarajan, Frank Klose, Jan Seidel, Clemens Ulrich Jan 2015

Strain-Induced Magnetic Phase Transition In Srcoo3−Δ Thin Films, S J. Callori, S Hu, Joel Bertinshaw, Zhilian Yue, S Danilkin, Xiaolin Wang, V Nagarajan, Frank Klose, Jan Seidel, Clemens Ulrich

Australian Institute for Innovative Materials - Papers

It has been well established that both in bulk at ambient pressure and for films under modest strains, cubic SrCoO3−δ (δ<0.2) is a ferromagnetic metal. Recent theoretical work, however, indicates that a magnetic phase transition to an antiferromagnetic structure could occur under large strain accompanied by a metal-insulator transition. We have observed a strain-induced ferromagnetic-to-antiferromagnetic phase transition in SrCoO3−δ films grown on DyScO3 substrates, which provide a large tensile epitaxial strain, as compared to ferromagnetic films under lower tensile strain on SrTiO3 substrates. Magnetometry results demonstrate the existence of antiferromagnetic spin correlations and neutron diffraction experiments provide a direct evidence for a G-type antiferromagnetic structure with Neél temperatures between TN∼135±10K and ∼325±10K, depending on the oxygen content of the samples. Therefore, our data experimentally confirm the predicted strain-induced magnetic phase transition to an antiferromagnetic state for SrCoO3−δ thin films under large epitaxial strain.


Ferroelectric And Magnetic Properties Of Aurivillius Bim+1ti3fem−3o3m+3 Thin Films, Tingting Jia, Hideo Kimura, Zhenxiang Cheng, Hongyang Zhao Jan 2015

Ferroelectric And Magnetic Properties Of Aurivillius Bim+1ti3fem−3o3m+3 Thin Films, Tingting Jia, Hideo Kimura, Zhenxiang Cheng, Hongyang Zhao

Australian Institute for Innovative Materials - Papers

Aurivillius Bim+1Ti3Fem−3O3m+3 (m = 4, 5, 6) thin films have been deposited by a pulsed laser deposition system. The x-ray diffraction patterns indicate the formation of orthorhombic phase. The remanent polarization (2Pr) of Bim+1Ti3Fem−3O3m+3 thin films is decreased with the m-number. Positive-up-negative-down measurements indicate the presence of ferroelectric (FE) polarization in as-obtained thin films. Piezoresponse force microscopy investigations confirm the existence of FE domains and the switchable polarization. Weak magnetic moment is detected in the Aurivillius films at room temperature. The present work …


Ultrafast Spin Polarization In A Multiferroic Manganite Bife0.5mn0.5o3 Thin Film, Zeyu Zhang, Zuanming Jin, Xian Lin, Zhenxiang Cheng, H Y. Zhao, Hideo Kimura, Guohong Ma Jan 2015

Ultrafast Spin Polarization In A Multiferroic Manganite Bife0.5mn0.5o3 Thin Film, Zeyu Zhang, Zuanming Jin, Xian Lin, Zhenxiang Cheng, H Y. Zhao, Hideo Kimura, Guohong Ma

Australian Institute for Innovative Materials - Papers

In this work, we present observations of ultrafast carrier dynamics and spin polarization in a multiferroic manganite BiFe0.5Mn0.5O3 film excited by linearly and circularly polarized femtosecond pulses, respectively. The d-band charge transfer transition is reasonably assigned to Γ3 → Γ5. The transient reflectivity decay on a time scale as fast as only 0.3 ps is consistent with the picture of ultrafast electron-phonon coupling. The ultrafast switching of polarization ellipticity (< 150 fs) originates from a transient coherent spin polarization by optical orientation. The ultrafast spin polarization switching is assigned to the Raman coherence process.


In Situ Anchoring Uniform Mno2 Nanosheets On Three-Dimensional Macroporous Graphene Thin-Films For Supercapacitor Electrodes, Yong Zhao, Yuena Meng, Haiping Wu, Yue Wang, Zhixiang Wei, Xiaojun Li, Peng Jiang Jan 2015

In Situ Anchoring Uniform Mno2 Nanosheets On Three-Dimensional Macroporous Graphene Thin-Films For Supercapacitor Electrodes, Yong Zhao, Yuena Meng, Haiping Wu, Yue Wang, Zhixiang Wei, Xiaojun Li, Peng Jiang

Australian Institute for Innovative Materials - Papers

We present a facile and efficient fabrication of 3D macroporous rGO/MnO2 nanosheet thin-films for supercapacitor electrodes. An amorphous-carbon-modified rGO thin-film is firstly prepared through a simple glucose and CaCO3 particle mediated template method. Then ultrathin MnO2 nanosheets are in situ synthesized on the rGO networks by the rapid and scalable redox reaction between KMnO4 and amorphous carbon. The fabricated three-dimensional porous hybrid thin-film shows a high specific capacitance of 245 F g-1 (based on the total mass of the film) at a scan rate of 2 mV s-1, a good rate capability of 143 F g-1 at 300 mV s-1, …


Increased Upconversion Performance For Thin Film Solar Cells: A Trimolecular Composition, Yuen Yap Cheng, Andrew Nattestad, Tim F. Schulze, Rowan W. Macqueen, Burkhard Fückel, Klaus Lips, Gordon G. Wallace, Tony Khoury, Maxwell J. Crossley, Timothy W. Schmidt Jan 2015

Increased Upconversion Performance For Thin Film Solar Cells: A Trimolecular Composition, Yuen Yap Cheng, Andrew Nattestad, Tim F. Schulze, Rowan W. Macqueen, Burkhard Fückel, Klaus Lips, Gordon G. Wallace, Tony Khoury, Maxwell J. Crossley, Timothy W. Schmidt

Australian Institute for Innovative Materials - Papers

Photochemical upconversion based on triplet-triplet annihilation (TTA-UC) is employed to enhance the short-circuit currents generated by two varieties of thin-film solar cells, a hydrogenated amorphous silicon (a-Si:H) solar cell and a dye-sensitized solar cell (DSC). TTA-UC is exploited to harvest transmitted sub-bandgap photons, combine their energies and re-radiate upconverted photons back towards the solar cells. In the present study we employ a dual-emitter TTA-UC system which allows for significantly improved UC quantum yields as compared to the previously used single-emitter TTA systems. In doing so we achieve record photo-current enhancement values for both the a-Si:H device and the DSC, surpassing …


Protein Nanorings Organized By Poly(Styrene-Block-Ethylene Oxide) Self-Assembled Thin Films, Jenny Malmström, Akshita Wason, Fergus Roache, N. Amy Yewdall, Mazdak Radjainia, Shanghai Wei, Michael J. Higgins, David Williams, Juliet A. Gerrard, Jadranka Travas-Sejdic Jan 2015

Protein Nanorings Organized By Poly(Styrene-Block-Ethylene Oxide) Self-Assembled Thin Films, Jenny Malmström, Akshita Wason, Fergus Roache, N. Amy Yewdall, Mazdak Radjainia, Shanghai Wei, Michael J. Higgins, David Williams, Juliet A. Gerrard, Jadranka Travas-Sejdic

Australian Institute for Innovative Materials - Papers

This study explores the use of block copolymer self-assembly to organize Lsmα, a protein which forms stable doughnut-shaped heptameric structures. Here, we have explored the idea that 2-D crystalline arrays of protein filaments can be prepared by stacking doughnut shaped Lsmα protein into the poly(ethylene oxide) blocks of a hexagonal microphase-separated polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer. We were able to demonstrate the coordinated assembly of such a complex hierarchical nanostructure. The key to success was the choice of solvent systems and protein functionalization that achieved sufficient compatibility whilst still promoting assembly. Unambiguous characterisation of these structures is difficult; however AFM …


An Investigation Of The Nanomechanical Properties Of 0.5ba(Ti0.8zr0.2)O3-0.5(Ba0.7ca0.3)Tio3 Thin Films, Zhong-Lan Cai, Zeng-Mei Wang, Huan-Huan Wang, Zhenxiang Cheng, Baowen Li, Xin-Li Guo, Hideo Kimura, Akira Kasahara Jan 2015

An Investigation Of The Nanomechanical Properties Of 0.5ba(Ti0.8zr0.2)O3-0.5(Ba0.7ca0.3)Tio3 Thin Films, Zhong-Lan Cai, Zeng-Mei Wang, Huan-Huan Wang, Zhenxiang Cheng, Baowen Li, Xin-Li Guo, Hideo Kimura, Akira Kasahara

Australian Institute for Innovative Materials - Papers

For practical application, the functional piezoelectric film in microelectromechanical systems should meet the requirement of physical properties, as well as the mechanical properties. In this article, 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 (0.5BZT-0.5BCT) thin films with varied properties were prepared on (100) Si substrates via a sol-gel technique at different annealing temperatures. The effects of the annealing temperature on the morphology, piezoelectricity, hardness, and elastic modulus were studied. Particular attention was paid to the surface frictional behavior of films, and the changes in the friction force can be radically explained in terms of differences in the hardness/elastic modulus ratio and the residual stress of films. …


Analysis Of Low-Field Isotropic Vortex Glass Containing Vortex Groups In Yba2cu3o7−X Thin Films Visualized By Scanning Squid Microscopy, Frederick Wells, Alexey V. Pan, Renshaw Wang, Sergey Fedoseev, Hans Hilgenkamp Jan 2015

Analysis Of Low-Field Isotropic Vortex Glass Containing Vortex Groups In Yba2cu3o7−X Thin Films Visualized By Scanning Squid Microscopy, Frederick Wells, Alexey V. Pan, Renshaw Wang, Sergey Fedoseev, Hans Hilgenkamp

Australian Institute for Innovative Materials - Papers

The glass-like vortex distribution in pulsed laser deposited YBa2Cu3O7 − x thin films is observed by scanning superconducting quantum interference device microscopy and analysed for ordering after cooling in magnetic fields significantly smaller than the Earth's field. Autocorrelation calculations on this distribution show a weak short-range positional order, while Delaunay triangulation shows a near-complete lack of orientational order. The distribution of these vortices is finally characterised as an isotropic vortex glass. Abnormally closely spaced groups of vortices, which are statistically unlikely to occur, are observed above a threshold magnetic field. The origin of these groups …


Pauli-Limited Effect In The Magnetic Phase Diagram Of Fesexte1−X Thin Films, Jincheng Zhuang, Zhen Li, Xun Xu, Li Wang, Wai Kong Yeoh, X Z. Xing, Zhixiang Shi, Xiaolin Wang, Yi Du, S X. Dou Jan 2015

Pauli-Limited Effect In The Magnetic Phase Diagram Of Fesexte1−X Thin Films, Jincheng Zhuang, Zhen Li, Xun Xu, Li Wang, Wai Kong Yeoh, X Z. Xing, Zhixiang Shi, Xiaolin Wang, Yi Du, S X. Dou

Australian Institute for Innovative Materials - Papers

We present a detailed investigation on the doping dependence of the upper critical fieldHc2(T) of FeSexTe1−xthin films (0.18 ≤ x ≤ 0.90) by measuring the electrical resistivity as a function of magnetic field. The Hc2(T) curves exhibit a downturn behavior with decreasing temperature in all the samples, owing to the Pauli-limited effect (spin paramagnetic effect). The Pauli-limited effect on the upper critical field can be monotonically modulated by variation of the Se/Te composition. Our results show that Te-doping induced disorder and excess Fe atoms give rise to enhancement of the Pauli-limited effect.


Thermoelectric Properties Of Ca3co4o9 And Ca2.8bi0.2co4o9 Thin Films In Their Island Formation Mode, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou Mar 2014

Thermoelectric Properties Of Ca3co4o9 And Ca2.8bi0.2co4o9 Thin Films In Their Island Formation Mode, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou

Shi Xue Dou

Ca3Co4O9 and Ca2.8Bi 0.2Co4O9 thin films were fabricated on LaAlO3 (LAO) substrate using pulsed laser deposition technique and were studied for their thermoelectric (TE) properties in Stranski-Krastanov mode for the first time. The thin films consisted of 3D clusters/islands on a 14-nm thick 2D layer with cluster density being higher for Ca 2.8Bi0.2Co4O9 thin films. The clusters also represent areas of dislocation and therefore act as carrier scattering centers, which leads to a temperature-activated type conductivity. Seebeck coefficient as high as 136 and 163 u V/K was measured for the Ca 3Co4O9 and Ca2.8Bi 0.2Co4O9 thin films, respectively, which is …


Anisotropy Of Crystal Growth Mechanisms, Dielectricity, And Magnetism Of Multiferroic Bi2femno6 Thin Films, P Liu, Z X. Cheng, Y Du, L Y. Feng, H Fang, Xiaolin Wang, S X. Dou Mar 2014

Anisotropy Of Crystal Growth Mechanisms, Dielectricity, And Magnetism Of Multiferroic Bi2femno6 Thin Films, P Liu, Z X. Cheng, Y Du, L Y. Feng, H Fang, Xiaolin Wang, S X. Dou

Shi Xue Dou

Epitaxial Bi2FeMnO6 (BFMO) thin films deposited on various Nb:SrTiO3 substrates show that the lattice parameters are very sensitive to epitaxial strains. Compressive and tensile strains are induced to the in-plane lattice constants of the (100) and (111) oriented films, respectively, while that of the (110) oriented thin film stay unstrained. The thin films also exhibit a strongly anisotropic growth habit depending on the substrate. Spiral growth, such as in the (100) BFMO film, is unique in samples prepared by pulsed laser deposition. Extrinsic dielectric constants at low frequencies are attributed to oxygen vacancies via the Maxwell-Wagner effect. All the samples …


Microscopic Model For Exchange Bias From Grain-Boundary Disorder In A Ferromagnet/Antiferromagnet Thin Film With A Nanocrystalline Microstructure, David L. Cortie, A G. Biternas, R W. Chantrell, Xiaolin Wang, Frank Klose Jan 2014

Microscopic Model For Exchange Bias From Grain-Boundary Disorder In A Ferromagnet/Antiferromagnet Thin Film With A Nanocrystalline Microstructure, David L. Cortie, A G. Biternas, R W. Chantrell, Xiaolin Wang, Frank Klose

Australian Institute for Innovative Materials - Papers

Monte Carlo spin simulations were coupled to a Voronoi microstructure-generator to predict the magnitude and behavior of exchange bias in a ferromagnet/antiferromagnet (AF) thin film bilayer with a nanocrystalline microstructure. Our model accounts for the effects of irregular grain-shapes, finite-sized particles, and the possible presence of local random-fields originating from the antiferromagnet's grain-boundary regions. As the grain-boundary represents a crystal-structure distortion, we model the local effect on the exchange constants in the Gaussian approximation which can cause regions resembling a spin glass confined to an unusual 2D topology. Although an ensemble of completely disconnected AF grains isolated by non-magnetic barriers …


Biocompatible Ionic Liquid-Biopolymer Electrolyte Enabled Thin And Compact Magnesium Air Batteries, Xiaoteng Jia, Yang Yang, Caiyun Wang, Chen Zhao, R Vijayaraghavan, Douglas R. Macfarlane, Maria Forsyth, Gordon G. Wallace Jan 2014

Biocompatible Ionic Liquid-Biopolymer Electrolyte Enabled Thin And Compact Magnesium Air Batteries, Xiaoteng Jia, Yang Yang, Caiyun Wang, Chen Zhao, R Vijayaraghavan, Douglas R. Macfarlane, Maria Forsyth, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

With the surge of interest in miniaturized implanted medical devices (IMDs), implantable power sources with small dimensions and biocompatibility are in high demand. Implanted battery/supercapacitor devices are commonly packaged within a case that occupies a large volume, making miniaturization difficult. In this study, we demonstrate a polymer electrolyte-enabled biocompatible magnesium-air battery device with a total thickness of approximately 300 μm. It consists of a biocompatible polypyrrole-para(toluene sulfonic acid) cathode and a bioresorbable magnesium alloy anode. The biocompatible electrolyte used is made of choline nitrate (ionic liquid) embedded in a biopolymer, chitosan. This polymer electrolyte is mechanically robust and offers a …


Significant Tunability Of Thin Film Functionalities Enabled By Manipulating Magnetic And Structural Nano-Domains, Igor A. Golovchanskiy, Alexey V. Pan, Sergey A. Fedoseev, Michael Higgins Jan 2014

Significant Tunability Of Thin Film Functionalities Enabled By Manipulating Magnetic And Structural Nano-Domains, Igor A. Golovchanskiy, Alexey V. Pan, Sergey A. Fedoseev, Michael Higgins

Australian Institute for Innovative Materials - Papers

The influence of laser frequency on the structure and physical properties of thin films grown by pulsed laser deposition has been studied. Different types of thin films, hard ferromagnetic FePt L10 and quasi-single crystal superconducting YBa2Cu3O7 (YBCO), have been used for demonstration of the effect. Significant structural modifications have been obtained for the films with similar thicknesses. These modifications are shown to dramatically control their corresponding properties, providing an instrumental ability for tuning the practical characteristics of the films by changing the laser frequency of their deposition. In particular, 20-fold increase of coercive field and modification of demagnetization mechanism are …


Thin, Tough, Ph-Sensitive Hydrogel Films With Rapid Load Recovery, Sina Naficy, Geoffrey M. Spinks, Gordon G. Wallace Jan 2014

Thin, Tough, Ph-Sensitive Hydrogel Films With Rapid Load Recovery, Sina Naficy, Geoffrey M. Spinks, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

Stimuli-responsive hydrogels are used as the building blocks of actuators and sensors. Their application has been limited, however, by their lack of mechanical strength and recovery from loading. Here, we report the preparation of pH-sensitive hydrogels as thin as 20 μm. The hydrogels are made of a polyether-based polyurethane and poly(acrylic acid). A simple method was employed to create hydrogels with thicknesses in the range of 20-570 μm. The hydrogel films volume changed by a factor of ∼2 when the pH was switched around the transition point (pH 4). Tensile extensibilities of up to ∼350% were maintained at each pH, …


Highly Oriented Lifepo4 Thin Film Electrodes Via Chemical Solution Deposition, Qi Li, Shulei Chou, Jiazhao Wang, Dongqi Shi, Hua-Kun Liu Jan 2014

Highly Oriented Lifepo4 Thin Film Electrodes Via Chemical Solution Deposition, Qi Li, Shulei Chou, Jiazhao Wang, Dongqi Shi, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Highly oriented LiFePO4 thin-film electrodes were fabricated via chemical solution deposition combined with spin coating. The effects of the precursor concentrations and types of substrates on microstructures and electrochemical performances were studied. Single-phase LiFePO4 with orientations perpendicular to the (211)/(020) and (311) planes prepared using stainless steel as substrate presents the capacity of 4.9 μAh•cm-2 and the apparent activation energy of 59.2 kJ•mol-1, indicating its great potential to be used as cathode material for lithium thin film batteries.


Pb Thin Films On Si(111): Local Density Of States And Defects, Stefan Eilers, Yi Du, S X. Dou Jan 2014

Pb Thin Films On Si(111): Local Density Of States And Defects, Stefan Eilers, Yi Du, S X. Dou

Australian Institute for Innovative Materials - Papers

Local density of states and atomic structure of the stripped incommensurate phase, the √3 x√7 phase and the 1 x 1 phase of a monolayer of Pb on Si(111) are characterized by scanning tunneling microscopy and spectroscopy. The dI/dV-images reveal congruent local density of states structures for the stripped incommensurate and the √3 x√ phase but suggest a hexagonal lattice of the local density of states for the 1x1 phase while the atomic structure consists of one more atom in the center of each hexagon. Vacancy defects and impurities show a depletion of local density of states for the stripped …


A Study Of Ti-Doped Wo3 Thin Films Using Comparative Theoretical And Experimental Approach, Aurelio Paez Jan 2014

A Study Of Ti-Doped Wo3 Thin Films Using Comparative Theoretical And Experimental Approach, Aurelio Paez

Open Access Theses & Dissertations

Metal oxides like Tungsten Oxide (WO3) are well documented and characterized in the literature, with uses in darkening windows and mirrors, flat computer displays, solar panel cooling, and sensors (of interest in this study). Ti doping of WO3 is less documented and the focus of this study. Sample thin films of pure WO3 and varyingly Ti doped WO3 were prepared using Radio Frequency magnetron sputtering (RF) (13.56 MHz) to grow thin films on a silicon substrate. This study aims to compare multiple Ti doping percentages in WO3 theoretically and then compare with experimental data taken from thin films of various …


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 …


The Control Of Time-Dependent Buckling Patterns In Thin Confined Elastomer Film, Brad Winton, Mihail Ionescu, S X. Dou Jun 2013

The Control Of Time-Dependent Buckling Patterns In Thin Confined Elastomer Film, Brad Winton, Mihail Ionescu, S X. Dou

Shi Xue Dou

Low energy metal ion implantation has been used to combine an easy “bottom-up” way of creating and tuning different topographic structures on submicron to micrometer scales with the embedding of a metallic element-rich functionalized layer at the surface for a variety of scientific and technological applications. The self-organizing and complex patterns of functionalized topographic structures are highly dependent on the implanted metal ion species, variations in the geometric confinement of the buckled areas on the larger unmodified elastomer film, and the boundary conditions of the buckled regions. Systematic investigations of these dependencies have been carried out via optical and atomic …


Correlation Between Structural Parameters And The Magnetocaloric Effect In Epitaxial La0.8ca0.2mno3/Laalo3 Thin Film, J C. Debnath, J H. Kim, Y Heo, A M. Strydom, S X. Dou Jun 2013

Correlation Between Structural Parameters And The Magnetocaloric Effect In Epitaxial La0.8ca0.2mno3/Laalo3 Thin Film, J C. Debnath, J H. Kim, Y Heo, A M. Strydom, S X. Dou

Shi Xue Dou

An epitaxial La0.8Ca0.2MnO3/LaAlO 3 (LCMO/LAO) thin film was fabricated using the pulsed laser deposition technique to evaluate the correlation between the crystal structure and the magnetocaloric effect. In our study, the LCMO film was 200 nm in thickness and appeared to have a strong out-of plane texture. We found that each column in the LCMO thin film layer is a domain which has a different ordering direction. These microscopic feature results in anisotropic properties of magnetization, entropy, and relative cooling power. The film exhibited a paramagnetic-to-ferromagnetic second order phase transition at 249 K. The lack of any hysteresis loss also …


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.


Modulation Of The Properties Of Thin Ferromagnetic Films With An Externally Applied Electric Field In Ferromagnetic/Piezoelectric/Ferromagnetic Hybrids, D Stamopoulos, M Zeibekis, Shujun Zhang Jan 2013

Modulation Of The Properties Of Thin Ferromagnetic Films With An Externally Applied Electric Field In Ferromagnetic/Piezoelectric/Ferromagnetic Hybrids, D Stamopoulos, M Zeibekis, Shujun Zhang

Australian Institute for Innovative Materials - Papers

In many cases, technological advances are based on artificial low-dimensional structures of heterogeneous constituents, thus called hybrids, that when come together they provide stand-alone entities that exhibit entirely different properties. Such hybrids are nowadays intensively studied since they are attractive for both basic research and oncoming practical applications. Here, we studied hybrids constituted of piezoelectric (PE) and ferromagnetic (FM) components in the form FM/PE/FM, ultimately aiming to provide means for the controlled modulation of the properties of the FM electrodes, originating from the strain imposed to them by the PE mediator when an electric field is applied. The PE component …


Correlation Between Structural Parameters And The Magnetocaloric Effect In Epitaxial La0.8ca0.2mno3/Laalo3 Thin Film, J C. Debnath, J H. Kim, Y Heo, A M. Strydom, S X. Dou Jan 2013

Correlation Between Structural Parameters And The Magnetocaloric Effect In Epitaxial La0.8ca0.2mno3/Laalo3 Thin Film, J C. Debnath, J H. Kim, Y Heo, A M. Strydom, S X. Dou

Australian Institute for Innovative Materials - Papers

An epitaxial La0.8Ca0.2MnO3/LaAlO 3 (LCMO/LAO) thin film was fabricated using the pulsed laser deposition technique to evaluate the correlation between the crystal structure and the magnetocaloric effect. In our study, the LCMO film was 200 nm in thickness and appeared to have a strong out-of plane texture. We found that each column in the LCMO thin film layer is a domain which has a different ordering direction. These microscopic feature results in anisotropic properties of magnetization, entropy, and relative cooling power. The film exhibited a paramagnetic-to-ferromagnetic second order phase transition at 249 K. The lack of any hysteresis loss also …


Enhanced Pinning In Superconducting Thin Films With Graded Pinning Landscapes, M Motta, F Colauto, W A. Ortiz, J Fritzsche, J Cuppens, W Gillijns, V V. Moshchalkov, T H. Johansen, A W Sanchez, A Silhanek Jan 2013

Enhanced Pinning In Superconducting Thin Films With Graded Pinning Landscapes, M Motta, F Colauto, W A. Ortiz, J Fritzsche, J Cuppens, W Gillijns, V V. Moshchalkov, T H. Johansen, A W Sanchez, A Silhanek

Australian Institute for Innovative Materials - Papers

A graded distribution of antidots in superconducting a-Mo 79Ge21 thin films has been investigated by magnetization and magneto-optical imaging measurements. The pinning landscape has maximum density at the sample border, decreasing linearly towards the center. Its overall performance is noticeably superior than that for a sample with uniformly distributed antidots: For high temperatures and low fields, the critical current is enhanced, whereas the region of thermomagnetic instabilities in the field-temperature diagram is significantly suppressed. These findings confirm the relevance of graded landscapes on the enhancement of pinning efficiency, as recently predicted by Misko and Nori [Phys. Rev. B 85, 184506 …


Thermoelectric Properties Of Ca3co4o9 And Ca2.8bi0.2co4o9 Thin Films In Their Island Formation Mode, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou Jan 2013

Thermoelectric Properties Of Ca3co4o9 And Ca2.8bi0.2co4o9 Thin Films In Their Island Formation Mode, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

Ca3Co4O9 and Ca2.8Bi 0.2Co4O9 thin films were fabricated on LaAlO3 (LAO) substrate using pulsed laser deposition technique and were studied for their thermoelectric (TE) properties in Stranski-Krastanov mode for the first time. The thin films consisted of 3D clusters/islands on a 14-nm thick 2D layer with cluster density being higher for Ca 2.8Bi0.2Co4O9 thin films. The clusters also represent areas of dislocation and therefore act as carrier scattering centers, which leads to a temperature-activated type conductivity. Seebeck coefficient as high as 136 and 163 u V/K was measured for the Ca 3Co4O9 and Ca2.8Bi 0.2Co4O9 thin films, respectively, which is …