Formation of point defects in strontium titanate

Walters, L.C.; Grace, R. E.

doi:10.1016/0022-3697(67)90114-x

Cited by 120 publications

(27 citation statements)

References 8 publications

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“…Changes of the electrical conductivity of undoped SrTiO3 with the oxygen partial pressure and thermoelectric measurements provided convincing evidence that p-type conductivity prevails in air or under oxidizing conditions, and n-type contributions become dominant under reducing conditions [4][5][6]. These authors also assumed that traces of acceptor impurities A might determine the actual transport properties of SrTiO 3 yielding an approximate neutrality condition…”

Section: Introductionmentioning

confidence: 91%

“…Equation 1 describes the approximate electroneutrality condition for both cases. According to several authors, the oxygen vacancies should remain doubly ionized [4,5]. The band gap of undoped SrTiO3 is higher than 3 eV [17,18], and the concentration of electronic charge carriers should be relatively low in the intermediate range of oxygen partial pressures.…”

Section: Introductionmentioning

confidence: 99%

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Combined effects of A-site deficiency and dopant content on the transport properties of Nb-doped strontium titanate

Abrantes

Labrincha

Frade

1997

Ionics

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Abstract. Strontium titanate based materials with A-site deficiency and Nb-additions were prepared to study the effects of these changes in composition on the transport properties and sinterability. X-ray diffraction was used for phase identification and to evaluate changes in the lattice parameters with composition. The dependence of the conductivity on the oxygen partial pressure was measured in the range 700-1000 ~ using an electrochemical oxygen pump to adjust the oxygen partial pressure in the furnace. Porous samples were used for this purpose to enhance the rate of exchange between the atmosphere and the samples. Changes in the composition have important effects on the relevant transport properties and also on the materials sinterability; this is especially true for Nb additions, which tend to suppress the p-type contribution under oxidizing conditions.

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Combined effects of A-site deficiency and dopant content on the transport properties of Nb-doped strontium titanate

Abrantes

Labrincha

Frade

1997

Ionics

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“…It is known that oxygen vacancies remain double ionized in quenched samples after annealing under vacuum, therefore, two free-electrons became available for each oxygen removed from the crystal lattice after the reduction process 16 . Several authors have studied the vacancy doping of SrTiO 3 in form of single crystals, thin films or ceramics [17][18][19][20] . Some of these authors have shown chemical diffusion coefficients for the SrTiO 3 crystal lattice using the Neumann solution of the Fick's second law carried out by in situ transient electrical resistivity measurements [18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

“…Several authors have studied the vacancy doping of SrTiO 3 in form of single crystals, thin films or ceramics [17][18][19][20] . Some of these authors have shown chemical diffusion coefficients for the SrTiO 3 crystal lattice using the Neumann solution of the Fick's second law carried out by in situ transient electrical resistivity measurements [18][19][20] . Additionally, in this paper we report that the solid-state kinetic models reviewed by Khawam and Flanagan 21 can describe the in situ electrical resistivity measurements as a function of time, which allows us to determine the energy involved in oxygen removal process from the SrTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Vacancy Doping in SrTiO3 Studied by in situ Electrical Resistivity

et al. 2018

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The kinetics of annealing to transform stoichiometric SrTiO 3 insulator into a vacancy-doped semiconductor-superconductor was revisited by in situ electrical resistivity measurements. SrTiO 3 single crystals were grown by Floating Zone Method. Using a homemade apparatus several electrical resistivity as a function of time were measured at different temperatures, which allows one to study the creation of vacancies during annealing under vacuum. The activation energy for the oxygen vacancies formation/charge doping in SrTiO 3 was estimated as 1.4±0.3 eV using solid-state kinetics approach.

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“…The high temperature defect chemistry and mechanism of electrical conduction in perovskite titanates such as BaTiO 3 and SrTiO 3 are well understood [9][10][11][12][13]. Undoped and nickel doped SrTiO 3 have been chosen as model substance, due to their simple cubic structure and availability in ceramic as well as in single crystalline form [14].…”

Section: Introductionmentioning

confidence: 99%

Dielectric relaxation and variable-range-hopping conduction in BaSn1−x Cr x O3 system

Upadhyay¹,

Kumar

2007

J Electroceram

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The possibility of formation of a solid solution in the system BaSn 1−x Cr x O 3 has been explored upto x≤0.20. It has been confirmed that single phase solid solution forms upto x≤0.10. Dielectric and conduction behaviour of single phase samples have been studied in the temperature range 400-610 K and frequency range 10 Hz-2 MHz. Two dielectric relaxation processes in two different frequency ranges have been observed. The temperature dependence of both dc and ac resistivity obey relation ρ=ρ o exp(B/T 1/4 ), indicative of variable range hopping conduction mechanism. The activation energy for dc conduction is higher than that for relaxation time (t) of low frequency dielectric relaxation process. It has been observed that activation energy for dielectric relaxation matches with activation energy for ac conductivity (at 100 kHz) for both the dielectric relaxation processes. Seebeck coefficient 'a' of the samples have been measured in the temperature range 350-650 K. Negative value of 'a' in the entire range of temperature measurement shows that conduction species are negatively charged. On the basis of value of activation energy for dc conduction and sign of Seebeck coefficient, conduction in the low temperature region (below 500 K) is attributed to hopping of weakly bonded electrons among Sn 2+ ⇔ Sn 4+ or Sn 3+ ⇔ Sn 4+ and that in the high temperature region (above 500 K) to hopping of doubly ionized oxygen vacancies V o À Á .

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Formation of point defects in strontium titanate

Cited by 120 publications

References 8 publications

Combined effects of A-site deficiency and dopant content on the transport properties of Nb-doped strontium titanate

Combined effects of A-site deficiency and dopant content on the transport properties of Nb-doped strontium titanate

Kinetics of Vacancy Doping in SrTiO3 Studied by in situ Electrical Resistivity

Dielectric relaxation and variable-range-hopping conduction in BaSn1−x Cr x O3 system

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