Suppression of oxygen diffusion by thin Al2O3 films grown on SrTiO3 studied using a monoenergetic positron beam

Uedono, Akira; Kiyohara, Masahiro; Yasui, Nobuyuki; Yamabe, Kikuo

doi:10.1063/1.1836010

Cited by 8 publications

(6 citation statements)

References 29 publications

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“…The possible candidate can be the oxygen vacancies (V O ) in the reduced oxygen atmosphere. The similar results have been published earlier for PAS studies of other perovskite materials [34,42] where vacuum annealing was used as a redox factor. The S values for pristine and oxygen treated films are the same within the experimental errors, which means that the oxygen treatment does not have effect on V O concentration.…”

Section: Defect Formation By Positron Annihilation Spectroscopysupporting

confidence: 86%

Tuned AFM–FM coupling by the formation of vacancy complex in Gd_0.6Ca_0.4MnO₃ thin film lattice

Beiranvand

Liedke

Haalisto

et al. 2021

J. Phys.: Condens. Matter

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The effect of in situ oxygen and vacuum annealings on the low bandwidth manganite Gd1−x Ca x MnO3 (GCMO) thin film with x = 0.4 was investigated. Based on the magnetic measurements, the AFM–FM coupling is suppressed by the vacuum annealing treatment via destroying the double exchange interaction and increasing the unit cell volume by converting the Mn4+ to the Mn3+. Consequently, resistance increases significantly compared to pristine film. The results are explained by a model obtained from the positron annihilation studies, where the vacuum annealing increased the annihilation lifetime in A and B sites due to the formation of vacancy complexes V A,B–V O, which was not the case in the pristine sample. The positron annihilation analysis indicated that most of the open volume defects have been detected in the interface region rather than on the subsurface layer and this result is confirmed by detailed x-ray reflection analysis. On the other hand, the effect of oxygen annealing on the unit cell volume and magnetization was insignificant. This is in agreement with positron annihilation results which demonstrated that the introduction of oxygen does not change the number of cation vacancies significantly. This work demonstrates that the modification of oxygen vacancies and vacancy complexes can tune magnetic and electronic structure of the epitaxial thin films to provide new functionalities in future applications.

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Section: Defect Formation By Positron Annihilation Spectroscopysupporting

confidence: 86%

Tuned AFM–FM coupling by the formation of vacancy complex in Gd_0.6Ca_0.4MnO₃ thin film lattice

Beiranvand

Liedke

Haalisto

et al. 2021

J. Phys.: Condens. Matter

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“…Atomic force microscopy (AFM) was used to observe sample surfaces, and positron annihilation was used to study the vacancy densities in all samples. The S-E curves were measured, and the mean implantation depth (Z) was estimated according to Z = 27.5 × E 1.7 /ρ, where E is the energy of implanted positrons and ρ is the density, given in g cm −3 [5][6][7]. According to the Z values and S-E curves, the S parameter at E > 5 keV corresponds to the bulk STO substrate and is marked S STO .…”

Section: Methodsmentioning

confidence: 99%

“…Besides, it is well known that V O density in a STO substrate can be easily increased or decreased by adjusting P O 2 during post-annealing [4][5][6]. Polycrystalline Al 2 O 3 films as passivation layers can be used on STO to effectively prevent further oxidation or reduction at 600 • C [7]. Similar epitaxial passivation layers are also necessary for STO or other ABO 3 -type oxides where V O migration can degrade their performance.…”

Section: Introductionmentioning

confidence: 99%

Epitaxial DyScO₃films as passivation layers suppress the diffusion of oxygen vacancies in SrTiO₃

Yuan¹,

Nishio²,

Lippmaa³

et al. 2009

J. Phys. D: Appl. Phys.

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The annealing behaviour of oxygen vacancies introduced by epitaxial growth of DyScO3 or SrTiO3 films on SrTiO3 substrates was studied by positron annihilation. Many oxygen vacancies (VO) were introduced near the interface in SrTiO3 substrates when 10 nm DyScO3 or 20 nm SrTiO3 films were grown by pulsed laser deposition at 10−2 Torr or 10−6 Torr oxygen pressure, respectively. Post-annealing in oxygen ambient could partly compensate those vacancies in the SrTiO3/SrTiO3 samples while no vacancy compensation was observed in the SrTiO3/DyScO3 or SrTiO3/DyScO3/SrTiO3 heterostructures. This suggests that epitaxial DyScO3 films can be used as passivation layers to suppress the diffusion of oxygen vacancies.

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“…The interface is metallic and conductivity is not eliminated by high-temperature annealing in oxygen atmosphere. A crystalline perovskite may be a good oxygen barrier so the conductivity would not be affected by annealing if oxygen vacancies are important for electrical conductivity [29,30]. Electrical conductivity in high pressure samples may also be triggered by mechanisms related to electrostatic discontinuity at the interface between polar NGO and non-polar STO in a similar way as discussed for the crystalline LAO/STO interfaces [14].…”

Section: Discussionmentioning

confidence: 98%

Cation stoichiometry and electrical transport properties of the NdGaO₃/(0 0 1)SrTiO₃interface

Kalabukhov¹,

Boikov²,

Serenkov³

et al. 2015

J. Phys.: Condens. Matter

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The interface formed between two wide band-gap insulators, NdGaO3 and SrTiO3 renders metallic behavior, similar to the LaAlO3/SrTiO3 interface. The interface conductivity depends strongly upon oxygen pressure during growth of the NdGaO3 film and subsequent annealing in oxygen. The conductivity of a (10 uc) NdGaO3/SrTiO3 film, pulsed laser deposited at low (pO2 = 10(-4) mbar) oxygen pressure, vanishes after annealing at 600 °C in oxygen atmosphere. For a similar interface formed at high oxygen pressure (pO2 = 0.3 mbar), the metallic conductivity remains also after post annealing. Medium energy ion spectroscopy (MEIS) in random (non-channeling) direction showed that a substantial part of Ga is missing in films deposited at low pressure, while optimal stoichiometry is approached in films deposited at high pressure. Aligned (channeling) MEIS likewise show that the Ga/Nd ratio approaches the stoichiometric value as the pressure is increased from 10(-4) to 0.3 mbar. This is interpreted as due to gallium desorption from a growing film at high temperature and low oxygen pressure while the re-evaporation of gallium is considerably suppressed at higher pressure. We discuss the possible role of stoichiometry on electrical transport properties.

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Suppression of oxygen diffusion by thin Al2O3 films grown on SrTiO3 studied using a monoenergetic positron beam

Abstract: Articles you may be interested inVariable energy positron beam analysis of vacancy defects in laser ablated Sr Ti O 3 thin films on Sr Ti O 3

Cited by 8 publications

References 29 publications

Tuned AFM–FM coupling by the formation of vacancy complex in Gd_0.6Ca_0.4MnO₃ thin film lattice

Tuned AFM–FM coupling by the formation of vacancy complex in Gd_0.6Ca_0.4MnO₃ thin film lattice

Epitaxial DyScO₃films as passivation layers suppress the diffusion of oxygen vacancies in SrTiO₃

Cation stoichiometry and electrical transport properties of the NdGaO₃/(0 0 1)SrTiO₃interface

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Suppression of oxygen diffusion by thin Al2O3 films grown on SrTiO3 studied using a monoenergetic positron beam

Abstract: Articles you may be interested inVariable energy positron beam analysis of vacancy defects in laser ablated Sr Ti O 3 thin films on Sr Ti O 3

Cited by 8 publications

References 29 publications

Tuned AFM–FM coupling by the formation of vacancy complex in Gd0.6Ca0.4MnO3 thin film lattice

Tuned AFM–FM coupling by the formation of vacancy complex in Gd0.6Ca0.4MnO3 thin film lattice

Epitaxial DyScO3films as passivation layers suppress the diffusion of oxygen vacancies in SrTiO3

Cation stoichiometry and electrical transport properties of the NdGaO3/(0 0 1)SrTiO3interface

Contact Info

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Resources

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Tuned AFM–FM coupling by the formation of vacancy complex in Gd_0.6Ca_0.4MnO₃ thin film lattice

Tuned AFM–FM coupling by the formation of vacancy complex in Gd_0.6Ca_0.4MnO₃ thin film lattice

Epitaxial DyScO₃films as passivation layers suppress the diffusion of oxygen vacancies in SrTiO₃

Cation stoichiometry and electrical transport properties of the NdGaO₃/(0 0 1)SrTiO₃interface