Ferroelectricity at room temperature in Pr-doped SrTiO3

Durán, A.; Martı́nez, E.; Dı́az, José A.; Siqueiros, J. M.

doi:10.1063/1.1903100

Cited by 79 publications

(83 citation statements)

References 17 publications

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“…This phase could not be accurately identified from the power diffraction database due to the weak intensities of the reflections. The possible secondary phases from the powders diffraction database might be Pr 5 are observed in the praseodymium oxide secondary phase. The inset shows the magnified micrograph of a secondary phase particle possessing a clearly different morphology than the matrix.…”

Section: Resultsmentioning

confidence: 99%

“…4 The majority of these phenomena were induced (observed) by modification of the perovskite lattice via either creation of oxygen vacancies and/or substitutional doping. Among the variety of dopants used to dope the "STO" lattice, praseodymium-doped STO displayed unique properties such as room-temperature ferroelectricity, 5 colossal dielectric constant, 6 photoluminescence, 7,8 and thermoelectric properties (specifically, a very large thermoelectric power factor). 9,10 The thermoelectric power factor, PF, is a measure of the potential of the electronic transport in a material for thermoelectric applications and is defined herein as PF ¼ a 2 rT, where a is the Seebeck coefficient, r the electrical conductivity, and T the absolute temperature in Kelvin.…”

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confidence: 99%

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New insights on the synthesis and electronic transport in bulk polycrystalline Pr-doped SrTiO3−δ

Dehkordi

Bhattacharya

Darroudi

et al. 2015

Journal of Applied Physics

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Effect of Pr substitution on structural and dielectric properties of SrTiO3 J. Appl. Phys. 112, 044106 (2012) Recently, we have reported a significant enhancement in the electronic and thermoelectric properties of bulk polycrystalline SrTiO 3 ceramics via praseodymium doping. This improvement was originated from the simultaneous enhancement in the thermoelectric power factor and reduction in thermal conductivity, which was contributed to the non-uniform distribution of Pr dopants. In order to further understand the underlying mechanism, we herein investigate the role of praseodymium doping source (Pr 2 O 3 versus Pr 6 O 11 ) on the synthesis and electronic transport in Pr-doped SrTiO 3 ceramics. It was observed that the high-temperature electronic transport properties are independent of the choice of praseodymium doping source for samples prepared following our synthesis strategy. Theoretical calculations were also performed in order to estimate the maximum achievable power factor and the corresponding optimal carrier concentration. The result suggests the possibility of further improvement of the power factor. This study should shed some light on the superior electronic transport in bulk polycrystalline Pr-doped SrTiO 3 ceramics and provide new insight on further improvement of the thermoelectric power factor. V C 2015 AIP Publishing LLC.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

New insights on the synthesis and electronic transport in bulk polycrystalline Pr-doped SrTiO3−δ

Dehkordi

Bhattacharya

Darroudi

et al. 2015

Journal of Applied Physics

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“…Stoichiometric ratios of SrCO 3 , TiO 2 , and Pr 6 O 11 , each of purity greater than 99.9% ͑Alpha Aesar͒, were thoroughly mixed and calcined at 1100°C for 3 h. The disk-shaped pellets were sintered at 1300°C for 2 h. It may, however, be mentioned that Pr can exist in 3+ and 4+ valence states, 14 15 a possibility of some fraction of the substituted Pr ions occupying the Ti site is also quite likely. In this paper, we have, however, not concerned ourselves with the problem of site occupancy of the substituted Pr ions in STO.…”

Section: Methodsmentioning

confidence: 99%

“…A possibility of stabilizing the ferroelectric phase at room temperature and above was theoretically predicted for biaxially strained STO 12 and was subsequently realized in a thin STO film grown on a DyScO 3 substrate. 13 Durán et al 14 have recently reported the existence of a ferroelectric phase in Pr-doped SrTiO 3 ceramics even at room temperature. So far no detailed study in this regard has been reported.…”

Section: Introductionmentioning

confidence: 99%

High-temperature relaxor ferroelectric behavior in Pr-dopedSrTiO3

et al. 2007

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Temperature-dependent Raman scattering, dielectric, and powder x-ray diffraction studies have been carried out on Pr-doped SrTiO 3 ceramic samples. Activation of TO 2 and TO 4 polar modes indicated increasing degree of polar distortion by Pr doping. Dielectric measurements revealed that the system exhibits dielectric relaxation peaks at ϳ500 K. The softening tendency of the polar TO 1 soft mode decreases with increasing Pr doping. X-ray diffraction results show no evidence of symmetry breaking across the dielectric peak temperatures. The system exhibits features of high-temperature relaxor ferroelectrics.

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“…1,2 STO is also a perfect prototype to investigate phase transition, 3 especially to understand the surface and interface structural configuration for the perovskite films grown on it. 4 Although ferroelectric properties were only reported through oxygen isotope exchange ͑ST 18 O͒, 3,5 and cation substitution, 6,7 recent theories and experiments validate the existence of ferroeletricity in STO thin films under strain. [8][9][10] He et al [11][12][13] systematically studied the structural phase transition of STO thin films under strain.…”

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confidence: 99%

Strain distribution in epitaxial SrTiO3 thin films

Zhai

Jiang

et al. 2006

Applied Physics Letters

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The lattice strain distributions of epitaxial SrTiO 3 films deposited on LaAlO 3 were investigated by in situ x-ray diffraction at the temperature range of 25-300 K, grazing incident x-ray diffraction, and high resolution x-ray diffraction. The nearly linear temperature dependence of the out-of-plane lattice constant of SrTiO 3 was observed in the measured temperature range. The depth distribution of the lattice strain at room temperature for SrTiO 3 films includes the surface layer, strained layer, and interface layer. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2424282͔ SrTiO 3 ͑STO͒ is an incipient ferroelectric material in perovskite structure, which has been extensively studied for its application in tunable microwave devices for having a large and variable dielectric constant. 1,2 STO is also a perfect prototype to investigate phase transition, 3 especially to understand the surface and interface structural configuration for the perovskite films grown on it. 4 Although ferroelectric properties were only reported through oxygen isotope exchange ͑ST 18 O͒, 3,5 and cation substitution, 6,7 recent theories and experiments validate the existence of ferroeletricity in STO thin films under strain. [8][9][10] He et al. [11][12][13] systematically studied the structural phase transition of STO thin films under strain. Devonshire 14 predicted the shift of the ferroelectric phase transition temperature ͑T c ͒ for STO thin films due to the biaxial strain. Haeni et al. 10 reported that the room temperature ferroelectricity appears for the tensile strained STO thin films on DyScO 3 substrates, although STO crystal is incipient ferroelectric. There is little work on the observation of distribution of lattice strain along the normal of sample surface for STO thin films.In this letter, the distribution of the lattice strain of the epitaxial STO films grown on LaAlO 3 ͑LAO͒ ͑001͒ substrate by laser molecular beam epitaxy ͑MBE͒ deposition ͑L-MBE͒ is investigated. The temperature dependence of the c-direction lattice constant ͑c-T curve͒ is nearly linear, which is different from that of the bulk. The depth dependence of the lattice strain is not homogeneous, which may be due to the competition between the elastic restore and the lattice mismatch between STO film and LAO substrate.STO films were grown on LAO ͑001͒ single crystal substrate in a L-MBE system. The technique was used to deposit STO on Si in our previous studies. 15,16 Briefly, a single crystal STO target was used to grow STO film. A KrF excimer laser was used in a repetition rate of 2 Hz. The substrate was heated to 770°C. The film thicknesses were 80, 150, and 280 nm from the measurement of a Dektax 3 ST surface profile. X-ray diffraction ͑XRD͒ ͑Cu K␣ radiation͒ analysis was performed using the /2 scan mode on a Rigaku Dmax-rB and a Bruker Advanced D8 X-ray diffractometer. The depth dependence of strain, which is related to the film thickness, was determined by grazing incident x-ray diffraction ͑surface x-ray diffraction͒, which was carried out on Be...

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Ferroelectricity at room temperature in Pr-doped SrTiO3

Cited by 79 publications

References 17 publications

New insights on the synthesis and electronic transport in bulk polycrystalline Pr-doped SrTiO3−δ

New insights on the synthesis and electronic transport in bulk polycrystalline Pr-doped SrTiO3−δ

High-temperature relaxor ferroelectric behavior in Pr-dopedSrTiO3

Strain distribution in epitaxial SrTiO3 thin films

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