Observation of a continuous phase transition in a shape-memory alloy
| Autor: | Lashley, J. C., Shapiro, S. M., Winn, B. L., Opeil, C. P., Manley, M. E., Alatas, A., Ratcliff, W., Park, T., Fisher, R. A., Mihaila, B., Riseborough, P., Salje, E. K. H., Smith, J. L. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 101, 135703 (2008) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.101.135703 |
| Popis: | Elastic neutron-scattering, inelastic x-ray scattering, specific-heat, and pressure-dependent electrical transport measurements have been made on single crystals of AuZn and Au_{0.52}Zn_{0.48} above and below their martensitic transition temperatures (T_M=64K and 45K, respectively). In each composition, elastic neutron scattering detects new commensurate Bragg peaks (modulation) appearing at Q = (1.33,0.67,0) at temperatures corresponding to each sample's T_M. Although the new Bragg peaks appear in a discontinuous manner in the Au_{0.52}Zn_{0.48} sample, they appear in a continuous manner in AuZn. Surprising us, the temperature dependence of the AuZn Bragg peak intensity and the specific-heat jump near the transition temperature are in favorable accord with a mean-field approximation. A Landau-theory-based fit to the pressure dependence of the transition temperature suggests the presence of a critical endpoint in the AuZn phase diagram located at T_M*=2.7K and p*=3.1GPa, with a quantum saturation temperature \theta_s=48.3 +/- 3.7K. Comment: 6 figures |
| Databáze: | arXiv |
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