1. Instituto de Ciencia de Materiales de Madrid
2. Consejo Superior de Investigaciones Científicas
3. 28049 Madrid
4. Spain
5. Institut Laue-Langevin
6. F-38042 Grenoble Cedex 9
7. France
8. Institute of Low Temperature and Structure Research
9. Polish Academy of Sciences
10. 50-422 Wroclaw
11. Poland