High metal–insulator transition temperature in La1−Sr MnO3 thin films grown in low oxygen partial pressure by molecular beam epitaxy

Ag -doped La 0.7 Ca 0.3 MnO 3 (LCMO) films were prepared on silicon substrate by RF magnetron sputtering. The dependences of transport properties on annealing temperature were explored. It is shown that the resistivity of the samples decreases and the metal–insulator transition temperature shifts to higher temperature with the increase in annealing temperature. Two metal–insulator transition temperatures are presented in the R – T plots of Ag -doped LCMO films, which can be explained by the Ag 1+ substitution of La 3+ to form La 1-x Ag x MnO 3 compound. Compared with LCMO thin films, Ag -doping can observably improve the TM-I and decrease the resistivity of the samples.

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Critical current density and microstructure of YBa2Cu3O7 thin films post-annealed at a low oxygen partial pressure

Journal of Superconductivity ◽

10.1007/bf00618058 ◽

1992 ◽

Vol 5 (2) ◽

pp. 143-147 ◽

Cited By ~ 4

Author(s):

A. Mogro-Campero ◽

L. G. Turner ◽

E. L. Hall

Keyword(s):

Thin Films ◽

Critical Current Density ◽

Oxygen Partial Pressure ◽

Partial Pressure ◽

Critical Current ◽

Current Density ◽

Low Oxygen

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Effect of Oxygen Partial Pressure on the Morphological Properties and the Photocatalytic Activities of Titania Thin Films on Unheated Substrates by Sputtering Deposition Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.770.18 ◽

2013 ◽

Vol 770 ◽

pp. 18-21 ◽

Cited By ~ 1

Author(s):

P. Pungboon Pansila ◽

Nirun Witit-Anun ◽

Surasing Chaiyakun

Keyword(s):

Thin Films ◽

Oxygen Partial Pressure ◽

Partial Pressure ◽

Anatase Phase ◽

Rutile Phase ◽

Morphological Properties ◽

Low Oxygen ◽

Working Pressure ◽

Sputtering Deposition ◽

Photocatalytic Activities

Titania (TiO2) thin films have been deposited using d.c. reactive unbalance magnetron sputtering on unheated substrate by various different oxygen partial pressures while working pressure and sputtering power were kept constant. A pure metallic titanium disk was used for sputtering target in atmospheric of the mixture gases between argon and oxygen. The X-ray diffraction (XRD) and atomic force microscopy (AFM) were used for characterization of characteristics structure and surface morphologies of the films, respectively. The optical transmission of the films were measured by spectrophotometer. The photocatalytic activities of the films were investigated from measurement of methylene blue degradation by using absorbance value after UV irradiation for 6 hr. The results show that the crystalline structures of the films showed the presence of single-anatase phase and mixed-anatase/rutile phase of TiO2 thin films. The surface morphology and photocatalytic activities of the films depend on oxygen partial pressure that grains size, surface roughness and thickness of the films were deceased when increasing oxygen partial pressure due to poisoning phenomenon and the high reactive gases. In addition, it was found that all TiO2 thin films were deposited by different oxygen partial pressure exhibit a good transparentness. Moreover, it was found that the TiO2 thin films deposited by used low oxygen partial pressure and single-anatase phase exhibited the best photocatalytic activity.

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Role of Oxygen Vacancies on the Ferroelectric Properties of Pzt Thin Films

MRS Proceedings ◽

10.1557/proc-243-393 ◽

1991 ◽

Vol 243 ◽

Cited By ~ 17

Author(s):

Chi Kong Kwok ◽

Seshu B. Desu

Keyword(s):

Thin Films ◽

Oxygen Partial Pressure ◽

Partial Pressure ◽

Vacancy Concentration ◽

Ferroelectric Properties ◽

Sol Gel ◽

Low Oxygen ◽

Partial Pressures ◽

Pzt Films

AbstractThe properties of ferroelectric thin films can be significantly influenced by the presence of point defects. The concentration of vacancies presented in these thin films is known to be one of the key parameters causing the degradation of these films when these films are subjected to polarization reversals.To study the effects of the vacancy concentration on the ferroelectric properties, sol gel PZT films and powders were annealed in different oxygen partial pressures. For the PZT films, the reduction of oxides to pure metals was not observed even with films annealed at 2×10−5 atmosphere of oxygen partial pressure. Samples annealed at low oxygen partial pressure (for instance, 10−3 and 2×10−5 atmosphere), which has more Pb and O2 depletions and consequently has more Pb and O2 vacancies, cannot be switched easily. The ratios of coercive field after and before fatigue increase as the defect concentrations of the annealed samples increase.

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