| Автор | S Uma Maheswari |
| Автор | K Venu |
| Автор | V S S Sastry |
| Дата выпуска | 1999-07-05 |
| dc.description | The influence of randomly quenched disorder in the incommensurate phases of Rb<sub>2</sub>(Zn<sub>1-x</sub>Cu<sub>x</sub>)Cl<sub>4</sub> (for x = 0.03), Rb<sub>2</sub>(Zn<sub>1-x</sub>Cd<sub>x</sub>)Cl<sub>4</sub> (for x = 0.03 and 0.05), Rb<sub>2</sub>(Zn<sub>1-x</sub>Hg<sub>x</sub>)Cl<sub>4</sub> (for x = 0.03 and 0.05) and Rb<sub>2</sub>Zn(Cl<sub>1-x</sub>Br<sub>x</sub>)<sub>4</sub> (for x = 0.01 and 0.03) is investigated via the amplitudon and phason dynamics using <sup>35</sup>Cl nuclear quadrupole resonance studies. Defect pinning at the metal and halogen sites in the prototype compound Rb<sub>2</sub>ZnCl<sub>4</sub> has been attempted for the first time and has yielded novel results. Quenched randomness at the metal site (Zn) in Rb<sub>2</sub>ZnCl<sub>4</sub> induced strong pinning of the modulation wave (irrespective of the size of the dopant compared to the host). This is evident from a temperature-independent and consequently T<sub>1</sub> unlike the case for impurity pinning at the other sites (cation and anion). The effect is enhanced with increasing concentration of the dopant. This result is contrasted with defect pinning at the halogen site (Cl) in Rb<sub>2</sub>ZnCl<sub>4</sub> with Br substitution which induced weak pinning of the modulation wave (temperature-dependent and consequently T<sub>1</sub>) similarly to substitution at the cation site as seen from earlier studies. Furthermore, the impurities have been categorized as random-field or random-potential type by evaluating the symmetry parameter (m) associated with the impurity. It is seen that Cu, Cd and Hg are random-field-type impurities inducing strong pinning of the modulation wave (m < 6; m = 6 for Rb<sub>2</sub>ZnCl<sub>4</sub>) while the Br impurity is of a random-potential type inducing a weak pinning of the modulation wave. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Evidence for site-specific strong and weak pinning of the modulation wave in the incommensurate phases of randomly quenched Rb<sub>2</sub>ZnCl<sub>4</sub> systems |
| Тип | paper |
| DOI | 10.1088/0953-8984/11/26/309 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 11 |
| Первая страница | 5065 |
| Последняя страница | 5082 |
| Аффилиация | S Uma Maheswari; School of Physics, University of Hyderabad, Hyderabad-500 046, India |
| Аффилиация | K Venu; School of Physics, University of Hyderabad, Hyderabad-500 046, India |
| Аффилиация | V S S Sastry; School of Physics, University of Hyderabad, Hyderabad-500 046, India |
| Выпуск | 26 |
