1. Structural instability in Ba[sub 1-x]K[sub x]BiO[sub 3].
- Author
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Gusakov, V., Zherlitsyn, S., Lu¨thi, B., Wolf, B., Ritter, F., Wichert, D., Bruls, G., Barilo, S., Shiryaev, S., Escribe-Filippini, C., and Tholence, J. L.
- Subjects
CRYSTALS spectra ,HYSTERESIS ,ELECTRONIC structure - Abstract
We report results of the ultrasonic investigation of Ba[sub 1−x]K[sub x]BiO[sub 3] single crystals for two potassium concentrations x ≈ 0.35 and x ≈ 0.47 in a wide temperature range. The softening of both the transverse c[sub 44] and the longitudinal c[sub 11] modes have been observed at temperatures between 200 K and 50 K. In the case of Ba[sub 0.65]K[sub 0.35]BiO[sub 3] a pronounced hysteresis was discovered. We proposed a model in which the softening of the elastic moduli, the hysteresis, and the maximum in the attenuation of sound can be explained by assuming a coupling of the acoustic modes with the anharmonic oscillations of O[sub 6] octahedra. [ABSTRACT FROM AUTHOR]
- Published
- 2001