1. a Insitut Laue-Langevin , 156X Centre de Tri, 38042 , Grenoble , France
2. d Institute of Nuclear Physics , 31-342 , Cracow , Poland
3. b L. V. Kirensky Institute of Physics , 60036 , Krasnoyarsk , USSR
4. c Institut für Kristallographic, RWTH Aachen and Institut für Festkörperforschung , KFA Jülich, D5170, FRG