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Brillouin scattering investigation of structural phase transitions in TMMC and TMMC:Cu
| Content Provider | Scilit |
|---|---|
| Author | Levola, T. Laiho, R. |
| Copyright Year | 1986 |
| Description | Journal: Journal of Physics C: Solid State Physics Structural phase transitions of tetramethyl ammonium manganese trichloride (TMMC) are investigated by using the Brillouin scattering method. The temperature dependences of the elastic coefficients $C_{11}$ and $C_{33}$ extracted from the experimental data are analysed by using the Landau theory of phase transitions. The step anomaly of $C_{33}$ observed at the order-disorder transition temperature $T_{c}$ can be attributed to a coupling between the order parameter and totally symmetric strains. An anomalous softening $C_{33}$ above $T_{c}$ indicates an interaction also between tetramethyl ammonium (TMA) molecules and the $MnCl_{3}$ chains. A new lattice anomaly, which the authors attribute to a change in the rotational degree of freedom of the TMA molecules, is observed at about 395K. Doping of TMMC with 2% of $Cu^{2+}$ creates a sequence of phases with transition temperatures at 92, 124 and 130K. An incommensurate phase stabilised by impurities may be involved in this sequence. Strong elastic scattering of light indicating a formation of needle-like domains along the c axis is observed in the doped crystals between 90 and 130K. |
| Related Links | http://iopscience.iop.org/article/10.1088/0022-3719/19/35/007/pdf |
| Ending Page | 6942 |
| Page Count | 12 |
| Starting Page | 6931 |
| ISSN | 00223719 |
| DOI | 10.1088/0022-3719/19/35/007 |
| Journal | Journal of Physics C: Solid State Physics |
| Issue Number | 35 |
| Volume Number | 19 |
| Language | English |
| Publisher | IOP Publishing |
| Publisher Date | 1986-12-20 |
| Access Restriction | Open |
| Subject Keyword | Journal: Journal of Physics C: Solid State Physics Phase Transitions Brillouin Scattering Tetramethyl Ammonium |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physics and Astronomy Condensed Matter Physics Engineering |
