Preparation and Properties of Multiferroic La-Doped BiFeO3 Thin Film

2012 ◽  
Vol 486 ◽  
pp. 417-421 ◽  
Author(s):  
Xiao Yan Zhang ◽  
Xi Wei Qi ◽  
Jian Quan Qi ◽  
Xuan Wang

Multiferroic La-doped Bi1-xLaxFeO3 thin films were prepared on conductive indium tin oxide (ITO)/glass substrates through a simple sol-gel process. The crystal structure of La-doped Bi1-xLaxFeO3 thin films annealed at different temperature was determined to be rhombohedral of R3m space and free of secondary phases. The grain size of La-doped BiFeO3 thin films tends to become larger and the grain boundary is gradually ambiguous compared to pure BiFeO3. The double remanent polarization 2Pr of Bi0.9La0.1FeO3 thin film annealed at 500°C is 6.66 µC/cm2, which is slightly improved than that of pure BiFeO3 thin film. With the increase of La-doping levels, the dielectric constant is increased and the dielectric loss is obviously decreased.

2011 ◽  
Vol 492 ◽  
pp. 202-205 ◽  
Author(s):  
Xi Wei Qi ◽  
Xiao Yan Zhang ◽  
Xuan Wang ◽  
Hai Bin Sun ◽  
Jian Quan Qi

BiFeO3 thin films were spin-coated on conductive indium tin oxide (ITO)/glass substrates by a simple sol-gel possess annealed at 470-590°C. The crystal structure of as-prepared BiFeO3 thin films annealed at different temperature was determined to be rhombohedral of R3m space and free of secondary phases was also confirmed. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 thin film was about 320 nm. The double remanent polarization 2Pr of BiFeO3 thin film annealed at 500°C is 2.5 μC/cm2 without applied field at room temperature. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of BiFeO3 thin film was 6.13 nm.


2012 ◽  
Vol 538-541 ◽  
pp. 78-82
Author(s):  
Xiao Yan Zhang ◽  
Xi Wei Qi ◽  
Jian Quan Qi ◽  
Xuan Wang ◽  
Huan Huan Chen ◽  
...  

Pure Bi0.9La0.1Fe1-xScxO3 (x = 0, 0.05, 0.10, 0.15, 0.20) (BLFSO) thin films were deposited on conductive indium tin oxide (ITO)/glass substrates through a simple sol-gel process. The effect of Sc doping on the XRD, microstructure, dielectric and ferroelectric properties of BLFO films was studied. Compared to counterparts of Bi0.9La0.1FeO3 (BLFO) film, the grain refinement of all films is obvious. When the value of Sc is 0.15, the double remanent polarization 2Pr is effectively enhanced with the extreme value of 17.7µC/cm2. The dielectric constant exhibits a trends of increase firstly and then decrease with the increase amount of scandium level.


2021 ◽  
Author(s):  
Younes Ziat ◽  
Hamza Belkhanchi ◽  
Maryama Hammi ◽  
Charaf Laghlimi ◽  
A Moutcine

Abstract Recently, the rise of two dimensional amorphous nanostructured thin films have ignited a big interest because of their intriguingly isotropic structural and physical properties leading to potential applications in the nano-optoelectronics. However, according to literature, most of optoelectronic properties are investigated on chalcogenides related heterostructures. This has motivated the present work aiming to provide a new platform for the fabrication, examination of the properties and the applications of 2D nanostructured thin films based on epoxy/silicone blend. Thin films of Epoxy/Silicone loaded with nitrogen doped carbon nanotubes (N-CNTs) were prepared by sol-gel method and deposited on Indium Tin Oxide (ITO) glass substrates at room temperature. Further examination of optical properties aimed the investigation of optical pseudo-gap and Urbach energy and enabled the determination of processed films thickness based on Manifacier and Swanepol method. The results indicated that the unloaded thin films have a direct optical transition with a value of 3.61 eV followed by noticeable shift towards narrowing gaps depending on the loading rate. Urbach's energy is 0.19 eV for the unloaded thin films, and varies from 0.43 to 1.33 eV for the loaded thin films with increasing the rate of N-CNTs. It is inversely variable with the optical pseudo-gap. Finally, Epoxy/Silicone loaded with N-CNTs nanocomposites films can be developed as active layers with specific optical characteristics, giving the possibility to be used in electro-optical applications.


2016 ◽  
Vol 78 (5-8) ◽  
Author(s):  
Khairul Aimi Yusof ◽  
Rohanieza Abdul Rahman ◽  
Muhammad AlHadi Zulkefle ◽  
Sukreen Hana Herman ◽  
Wan Fazlida Hanim Abdullah

Titanium dioxide (TiO2) thin films were fabricated on indium tin oxide (ITO) glass substrates using the spin coating technique and further were implemented as sensing membranes of the extended gate field effect transistor (EGFET) based pH sensor. The as-deposited thin films were annealed at different temperatures from 200 - 600 °C in room ambient for 20 min. The effects of different annealing temperatures on electrical and crystalline properties were analyzed by I-V two point probes measurement and X-ray diffraction respectively. Meanwhile, the surface morphology of thin films was observed by field emission scanning electron microscope (FESEM). We then measured the transfer characteristics (ID-VG) of the TiO2/ITO sensing membrane using a semiconductor parametric device analyzer for sensor characterization. It was found that, TiO2/ITO sensing membrane annealed at 300 °C achieved higher sensitivity and good linearity of 51.48 mV/pH and 0.99415, respectively in the pH buffer solutions of 4, 7, 10, and 12. Thin film annealed at 300 °C gives higher conductivity thin film of 384.62 S/m. We found that the conductivity of TiO2/ITO thin films was proportional with the sensitivity of sensing membrane.  


2013 ◽  
Vol 537 ◽  
pp. 109-113
Author(s):  
Xi Wei Qi ◽  
Xiao Yan Zhang ◽  
Xuan Wang ◽  
Hai Bin Sun ◽  
Jian Quan Qi

A series of Dy doped La and Sc solution of BiFeO3 thin films have been prepared by using spin-coating process on conductive indium tin oxide (ITO)/glass substrates, which a simple sol-gel possess is applied and annealed at 500°C. With the increase of content of Dy, the strongest peak (110) of La and Sc solution BiFeO3 film tends to further broaden. There is no second phase existence within the present Dy doping level. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 film was about 370 nm. For Dy doping level is 0.05, the maximum double remanent polarization 2Pr of as-prepared BiFeO3 thin film is15.44 μC/cm2. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of as-prepared BiFeO3 thin film is 2.11 nm. The dielectric constant of as-prepared films tends to firstly increase and then decrease with the increase of Dy content


2007 ◽  
Vol 21 (18n19) ◽  
pp. 3404-3411
Author(s):  
M. C. KAO ◽  
H. Z. CHEN ◽  
S. L. YOUNG ◽  
C. C. LIN ◽  
C. C. YU

LiTaO 3 thin films were deposited on Pt / Ti / SiO 2/ Si substrates by means of a sol-gel spin-coating technology and rapid thermal annealing (RTA). The influence of various annealing treatments on the characteristics of the thin films were studied by varying the single-annealed-layer thickness (50 ~ 200 nm ) and heating temperatures (500 ~ 800° C ) of the samples. Experimental results reveal that the single-annealed-layer strongly influences grain size, dielectricity and ferroelectricity of LiTaO 3 thin films. The grain size of LiTaO 3 thin film decreases slightly with increasing thickness of the single-annealed-layer, and highly c-axis orientated LiTaO 3 films can be obtained for a single-annealed-layer of 50 nm. When the thickness of the single-annealed-layer was increased from 50 to 200 nm, the relative dielectric constant of LiTaO 3 thin film decreased from 65 to 35, but the dielectric loss factor (tanδ) was increased. The LiTaO 3 films with the single-annealed-layer of 50 nm showed excellent ferroelectric properties in terms of a remanent polarization ( P r) of 12.3 μ C /cm2 (Ec ∼ 60 kV/cm), and a low current density of 5.2×l0-8 A /cm2 at 20 kV/cm.


2008 ◽  
Vol 15 (01n02) ◽  
pp. 13-18
Author(s):  
X. T. LI ◽  
C. WU ◽  
W. J. WENG ◽  
G. R. HAN ◽  
P. Y. DU

A series of ( Pb 0.4 Sr 0.6)1-x La 2x/3 TiO 3 (PSLT) thin films were deposited on ITO/glass substrates by sol–gel technique. Their phase status, surface morphology, and dielectric properties were studied by X-ray diffraction, scanning electron microscope, and impedance analyzer, respectively. Results show that the PSLT thin films were consisted of tetragonal perovskite phase PSLT thin films for x < 0.4, and cubic perovskite phase PSLT thin films for x > 0.4. Dielectric properties such as dielectric constants, dielectric tunabilitis, and inharmonic coefficient were characterized as a function of the film composition.


Author(s):  
Kexin Li ◽  
Wanyun Zhang ◽  
Kaixin Guo ◽  
Ruirui Cui ◽  
Chaoyong Deng ◽  
...  

Abstract Pure bismuth ferrite (BiFeO3, BFO) and ZnO thin films, as well as BFO/ZnO and ZnO/BFO composite thin films were successfully deposited by a sol-gel process on Pt/Ti/SiO2/Si and FTO/glass substrates, respectively. The chemical composition, surface morphology, optical properties, and multiferroicity were systematically investigated. X-ray diffraction and electron microscopy measurements were used to determine the crystalline phase and to analyze the surface morphology. Evidently, the absorption edges of both BFO/ZnO and ZnO/BFO films show a redshift, broadening the absorption range. The leakage current density decreases with the introduction of ZnO, and the ferroelectricity was significantly improved of the bilayers. Thereinto, BFO/ZnO and ZnO/BFO show the highest saturate polarization (2P s) of 46.7 μc/cm2 and the maximum remanent polarization (2P r) of 18.5 μc/cm2, respectively. Meanwhile, the magnetization measurement revealed that both BFO/ZnO and ZnO/BFO exhibiting an enhanced magnetization, especially, BFO/ZnO displays the highest saturation magnetization (2M s, 68.87 emu/cm3) and remanent magnetization (2M r, 4.87 emu/cm3).


2010 ◽  
Vol 24 (08) ◽  
pp. 807-816 ◽  
Author(s):  
M. VISHWAS ◽  
SUDHIR KUMAR SHARMA ◽  
K. NARASIMHA RAO ◽  
S. MOHAN ◽  
K. V. ARJUNA GOWDA ◽  
...  

TiO 2 thin films have been deposited on glass and indium tin oxide (ITO) coated glass substrates by sol–gel technique. The influence of annealing temperature on the structural, morphological and optical properties has been examined. X-ray diffraction (XRD) results reveal the amorphous nature of the as-deposited film whereas the annealed films are found to be in the crystalline anatase phase. The surface morphology of the films at different annealing temperatures has been examined by atomic force microscopy (AFM). The in situ surface morphology of the as-deposited and annealed TiO 2 films has also been examined by optical polaromicrograph (OPM). TiO 2 films infatuated different structural and surface features with variation of annealing temperature. The optical studies on these films suggest their possible usage in sun-shielding applications.


1999 ◽  
Vol 606 ◽  
Author(s):  
Keishi Nishio ◽  
Jirawat Thongrueng ◽  
Yuichi Watanabe ◽  
Toshio Tsuchiya

AbstructWe succeeded in the preparation of strontium-barium niobate (Sr0.3Ba0.7Nb2O6 : SBN30)that have a tetragonal tungsten bronze type structure thin films on SrTiO3 (100), STO, or La doped SrTiO3 (100), LSTO, single crystal substrates by a spin coating process. LSTO substrate can be used for electrode. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)5 as raw materials, and acetic acid and diethylene glycol monomethyl ether as solvents. The coating thin films were sintered at temperature from 700 to 1000°C for 10 min in air. It was confirmed that the thin films on STO substrate sintered above 700°C were in the epitaxial growth because the 16 diffraction spots were observed on the pole figure using (121) reflection. The <130> and <310> direction of the thin film on STO were oriented with the c-axis in parallel to the substrate surface. However, the diffraction spots of thin film on LSTO substrate sintered at 700°C were corresponds to the expected pattern for (110).


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