Local distortions in the BiO6-octahedra sublattice of BaPb Bi1−O3 as seen by 137Ba NMR/NQR
| Autor: | Yu.V. Piskunov, Yu. I. Zhdanov, Eu.Yu. Medvedev, R.N. Pletnev, K. N. Mikhalev, S. V. Verkhovskii, A. Gerashenko, K. Kumagai, S. M. Cheshnitskii, I.V. Sagaradze, A. Yu. Yakubovskii |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Superconductivity
Materials science Condensed matter physics Energy Engineering and Power Technology chemistry.chemical_element Barium Activation energy Condensed Matter Physics Spectral line Electronic Optical and Magnetic Materials chemistry Octahedron Phase (matter) Quadrupole Condensed Matter::Strongly Correlated Electrons Electrical and Electronic Engineering Electric field gradient |
| Zdroj: | Physica C: Superconductivity. 274:209-220 |
| ISSN: | 0921-4534 |
| DOI: | 10.1016/s0921-4534(96)00674-0 |
| Popis: | The 137 Ba NMR and NQR spectra as well as the spin-lattice relaxation rate were measured for the first time in the BaPb x Bi 1− x O 3 samples with x = 0.91 (normal metal), x = 0.75 (superconductor) and x = 0.64 (semiconductor). The strong quadrupole broadening of the NMR lines with lowering temperature was found for all the samples. An evolution of static distortions in the BiO 6 -octahedra sublattice along with asymmetry of the electric field gradient at the Ba-sites is discussed. This asymmetry caused by the nearest non-cubic surrounding of barium is originated from the temperature dependent tilt of BiO 6 -octahedra. Spin-lattice relaxation rate of 137 Ba is monitored by fluctuating part of electric field gradient at the Ba-site and its exponential growth at low temperatures evidences the thermally activated collective rotations of BiO 6 -octahedra around their static tilt. An activation energy and a strength of these dynamic distortions are evaluated and found to increase in going from metallic to semiconducting phase of BaPb x Bi 1− x O 3 . |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect