1
|
Brillouin light scattering in niobium doped lead zirconate single crystal. Sci Rep 2022; 12:13066. [PMID: 35906398 PMCID: PMC9338233 DOI: 10.1038/s41598-022-17392-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 07/25/2022] [Indexed: 11/09/2022] Open
Abstract
Brillouin light scattering experiments were performed for lead zirconate single crystals doped with niobium. Special attention was paid to the elastic mode softening near phase transition temperatures. The results are compared with data obtained by Raman light scattering experiments. We observed that the interaction between acoustic and optic modes is responsible for symmetry breaking far above TC, leading to polar regions' appearance. No changes in the acoustic mode frequency and its damping are observed at TC, where ε(T) exhibits a maximum value. The absence of these changes and the central peak observed in Raman experiments suggest that the phase transition at TC is mainly of the order–disorder type. The origin of other phase transitions is discussed as well.
Collapse
|
2
|
Magnetic field driven phase transitions in EuTiO 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:02LT01. [PMID: 34638109 DOI: 10.1088/1361-648x/ac2f11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
The influence of an external static magnetic field (up to 480 mT) on the structural properties of EuTiO3(ETO) polycrystalline samples was examined by powder XRD at the Elettra synchrotron facilities in the temperature range 100-300 K. While the cubic to tetragonal structural phase transition temperature in this magnetic field range remains almost unaffected, significant lattice effects appear at two characteristic temperatures (∼200 K and ∼250 K), which become more pronounced at a critical threshold field. At ∼200 K a change in the sign of magnetostriction is detected attributed to a modification of the local magnetic properties from intrinsic ferromagnetism to intrinsic antiferromagnetism. These data are a clear indication that strong spin-lattice interactions govern also the high temperature phase of ETO and trigger the appearance of magnetic domain formation and phase transitions.
Collapse
|
3
|
Hidden magnetism in the paramagnetic phase of EuTiO₃. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:496003. [PMID: 26596645 DOI: 10.1088/0953-8984/27/49/496003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
EuTiO3 is investigated experimentally by temperature dependent conductivity and dielectric constant measurements. Both data sets evidence a crossover behavior in their temperature dependence around T * ~ 200 K indicating a change of the electrical and magnetic behavior of EuTiO3 as already observed by muon spin rotation (μSR) measurements. Around T ' = 80 K an additional anomaly appears which is consistent with previous resonant ultrasound spectroscopy (RUS) data. By applying a magnetic field (1.2 T at room temperature) the bulk conductivity is anomalously enhanced by more than one order of magnitude. The bulk dielectric constant ε(r) decreases with increasing temperature and is enhanced by the magnetic field by up to 22%. All data reveal a substantial hysteresis which is diminished in a magnetic field. The unusual magnetic field dependence of all quantities is suggested to stem from magnetically active domain walls which are mobile between the structural phase transition temperature (T(S) = 282 K) and T * and are pinned below it.
Collapse
|
4
|
Lattice and polarizability mediated spin activity in EuTiO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:022202. [PMID: 24275498 DOI: 10.1088/0953-8984/26/2/022202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
EuTiO3 is shown to exhibit novel strong spin-charge-lattice coupling deep in the paramagnetic phase. Its existence is evidenced by an, until now, unknown response of the paramagnetic susceptibility at temperatures exceeding the structural phase transition temperature T(S) = 282 K. The 'extra' features in the susceptibility follow the rotational soft zone boundary mode temperature dependence above and below TS. The theoretical modeling consistently reproduces this behavior and provides reasoning for the stabilization of the soft optic mode other than quantum fluctuations.
Collapse
|
5
|
Nonlinear pressure dependence of TN in almost multiferroic EuTiO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:376002. [PMID: 23963024 DOI: 10.1088/0953-8984/25/37/376002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The antiferromagnetic (AFM) phase transition temperature TN of EuTiO3 has been studied as a function of pressure p. The data reveal a nonlinear dependence of TN on p with TN increasing with increasing pressure. The exchange interactions exhibit an analogous dependence on p as TN (if the absolute value of the nearest neighbor interaction is considered) and there is evidence that the AFM transition is robust with increasing pressure. The corresponding Weiss temperature ΘW remains anomalous since it always exhibits positive values. The data are analyzed within the Bloch power law model and provide excellent agreement with experiment.
Collapse
|
6
|
Magnetic field enhanced structural instability in EuTiO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:492201. [PMID: 23128481 DOI: 10.1088/0953-8984/24/49/492201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
EuTiO(3) undergoes a structural phase transition from cubic to tetragonal at T(S) = 282 K which is not accompanied by any long range magnetic order. However, it is related to the oxygen octahedral rotation driven by a zone boundary acoustic mode softening. Here, we show that this displacive second order structural phase transition can be shifted to higher temperatures by the application of an external magnetic field (ΔT(S) ∼ 4 K for μ(0)H = 9 T). This observed field dependence is in agreement with theoretical predictions based on a coupled spin-anharmonic-phonon interaction model.
Collapse
|
7
|
Competing interactions and the isotope effect in colossal magnetoresistance materials. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/13642819908206786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
8
|
Oxygen isotope effects on the superconducting transition and magnetic states within the phase diagram of Y1-xPrxBa2Cu3O7-delta. PHYSICAL REVIEW LETTERS 2008; 101:077001. [PMID: 18764566 DOI: 10.1103/physrevlett.101.077001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Indexed: 05/26/2023]
Abstract
The various phases observed in all cuprate superconductors [superconducting (SC), spin-glass (SG), and antiferromagnetic (AFM)] were investigated with respect to oxygen-isotope (16O/18O) effects, using here as a prototype system of cuprates Y1-xPrxBa2Cu3O7-delta. All phases exhibit an isotope effect which is strongest where the respective phase terminates. In addition, the isotope effects on the magnetic phases (SG and AFM) are sign reversed as compared to the one on the superconducting phase. In the coexistence regime of the SG and SC phase a two-component behavior is observed where the isotope induced decrease of the superfluid density leads to a corresponding enhancement in the SG related density.
Collapse
|
9
|
Multiple gap symmetries for the order parameter of cuprate superconductors from penetration depth measurements. PHYSICAL REVIEW LETTERS 2007; 99:237601. [PMID: 18233411 DOI: 10.1103/physrevlett.99.237601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Indexed: 05/25/2023]
Abstract
The temperature dependence of the London penetration depth lambda was measured for an untwinned single crystal of YBa_{2}Cu_{3}O_{7-delta} along the three principal crystallographic directions (a, b, and c). Both in-plane components (lambda_{a};{-2} and lambda_{b};{-2}) show an inflection point in their temperature dependence which is absent in the component along the c direction (lambda_{c};{-2}). The data provide convincing evidence that the in-plane superconducting order parameter is a mixture of (s+d)-wave symmetry whereas it is mainly s wave along the c direction. In conjunction with previous results it is concluded that coupled s+d-order parameters are universal and intrinsic to cuprate superconductors.
Collapse
|
10
|
Polar-Soft-Mode-Driven Structural Phase Transition in SrTiO3. PHYSICAL REVIEW LETTERS 2007; 99:167603. [PMID: 17995295 DOI: 10.1103/physrevlett.99.167603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Indexed: 05/25/2023]
Abstract
The structural phase transition of SrTiO3 at 105 K, which has been believed to be independent of the ferroelectric soft mode [Phys. Rev. 177, 858 (1969)], is shown, on the contrary, to be driven by the same long-wavelength polar instability. Isotope replacement of 16O by 18O is predicted to cause an increase in the structural phase transition temperature by 3.8 K. In both isotopic cases, dynamical polarizability-induced ferroelastic-type cluster formation takes place above the structural phase transition, which is intrinsic and a consequence of electron-lattice driven mode-mode coupling. Distinct length and time scales are identified. The precursor domains are evidence that order-disorder effects coexist with displacive dynamics.
Collapse
|
11
|
Experimental evidence for two gaps in the high-temperature La1.83Sr0.17CuO4 superconductor. PHYSICAL REVIEW LETTERS 2007; 98:057007. [PMID: 17358890 DOI: 10.1103/physrevlett.98.057007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Indexed: 05/14/2023]
Abstract
The in-plane magnetic field penetration depth (lambda(ab)) in single-crystal La1.83Sr0.17CuO4 was investigated by muon-spin rotation (muSR). The temperature dependence of lambda(ab)(-2) has an inflection point around 10-15 K, suggesting the presence of two superconducting gaps: a large gap (Delta(1)(d)) with d-wave and a small gap (Delta(2)(s)) with s-wave symmetry. The zero-temperature values of the gaps at mu(0)H=0.02 T were found to be Delta(1)(d)(0)=8.2(1) meV and Delta(2)(s)(0)=1.57(8) meV.
Collapse
|
12
|
|
13
|
Three-dimensional gap structure in layered high-temperature superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:R11968-R11971. [PMID: 9982900 DOI: 10.1103/physrevb.53.r11968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
14
|
Quasiharmonic periodic traveling-wave solutions in anharmonic potentials. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:11521-11530. [PMID: 9982771 DOI: 10.1103/physrevb.53.11521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
15
|
Erratum: Nonlinear travelling waves in ferroelectrics. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:6929. [PMID: 9981923 DOI: 10.1103/physrevb.52.6929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
16
|
Anharmonicity in the c direction of high-Tc oxides. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:6640-6644. [PMID: 9977198 DOI: 10.1103/physrevb.51.6640] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
17
|
Anharmonic electron and phonon effects in the c-axis infrared conductivity of high-Tc oxides. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:3246-3249. [PMID: 9979119 DOI: 10.1103/physrevb.51.3246] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
18
|
Crossover from a displacive to an order-disorder transition in the nonlinear-polarizability model. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:2473-2479. [PMID: 10006297 DOI: 10.1103/physrevb.47.2473] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
19
|
Anharmonicity-induced multiphonon processes in high-temperature superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:2853-2856. [PMID: 9999869 DOI: 10.1103/physrevb.44.2853] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
20
|
Importance of structural instability to high-temperature superconductivity. PHYSICAL REVIEW LETTERS 1991; 67:512-515. [PMID: 10044913 DOI: 10.1103/physrevlett.67.512] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
21
|
Unconventional electron-phonon interactions in high-temperature superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 43:13728-13731. [PMID: 9997233 DOI: 10.1103/physrevb.43.13728] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
22
|
Isotope effect on displacive-type ferroelectric-phase-transition temperatures. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:9581-9584. [PMID: 9993321 DOI: 10.1103/physrevb.41.9581] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
23
|
Interplay of polarizability and ionicity in IV-VI compounds. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 40:11639-11643. [PMID: 9991764 DOI: 10.1103/physrevb.40.11639] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
24
|
Erratum: Possibility of a common origin to ferroelectricity and superconductivity in oxides. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:12340. [PMID: 9948087 DOI: 10.1103/physrevb.39.12340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
25
|
Applications of the polarizability model to various displacive-type ferroelectric systems. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:9214-9223. [PMID: 9947650 DOI: 10.1103/physrevb.39.9214] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
26
|
|
27
|
Possibility of a common origin to ferroelectricity and superconductivity in oxides. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:207-214. [PMID: 9947139 DOI: 10.1103/physrevb.39.207] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
28
|
Nonlinear travelling waves in ferroelectrics. PHYSICAL REVIEW. B, CONDENSED MATTER 1987; 36:630-638. [PMID: 9942081 DOI: 10.1103/physrevb.36.630] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
29
|
Theory of ferroelectricity: The polarizability model. PHYSICAL REVIEW. B, CONDENSED MATTER 1987; 35:4840-4849. [PMID: 9940659 DOI: 10.1103/physrevb.35.4840] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
30
|
|