NMR and dielectric studies of NH4+ motion in some ammonium alums.
Abstract
Motion of NH4+ and H2O in NH4Ga(SO4)2 · 12H2O and NH4In(SO4)2 · 12H2O has been studied with NMR and dielectric methods. Above the phase transitions at 101 to 111 K and 126 to 128 K, respectively, the NH4+ ions hop and reorient by 90° between two sites, as in NH4Al(SO4)2 · 12H2O. This motion is frozen below Tc.
- Publication:
-
Physica Scripta
- Pub Date:
- September 1987
- DOI:
- Bibcode:
- 1987PhyS...36..559F