| Popis: |
In order to resolve the crystal structure and the corresponding space group of the tetrahedrally coordinated II–III 2 –V I 4 defective semiconductor ZnGa 2 Se 4 , a study of the magnetic susceptibility of the alloy system Zn 1− z Mn z Ga 2 Se 4 is performed. The analysis of the Curie–Weiss temperature confirms, consistently with the phase diagram previously reported, that the room temperature crystal structure of the alloy system Zn 1− z Mn z Ga 2 Se 4 in all the composition ranges ( 0 ≤ z ≤ 1 ) is of defect chalcopyrite type with space group I 4 while samples obtained at temperatures higher than about 500 °C, which are rapidly cooled to room temperature, crystallizes in the partially disordered stannite-type structure I 4 2 m . Hence, a careful process of crystal growth of this system, including a study of the phase diagram, annealing at adequate temperature, and slow cooling of the samples is necessary in order to obtain specimens in the ordered phase. |
Full Text from ScienceDirect