title: NMR study of monomethylammonium cation in (CH3NH3)5Bi2Cl11 ferroelectric polycrystal.
abstract: Spin-lattice relaxation times T1 and T1p are determined for protons in three polycrystals (CH3NH3)5Bi2Cl11, (CD3NH3)5Bi2Cl11 and (CH3ND3)5Bi2Cl11. The temperature dependencies of the relaxation times obtained for (CH3NH3)5Bi2Cl11 and (CD3NH3)5Bi2Cl11 are interpreted as a result of correlated motions of the three-proton groups of the monomethylammonium cation. The minimum of the T1p relaxation time is explained as a result of the oscillations of the symmetry axis of the whole cation.
authors.affiliation: Institute of Molecular Physics, PAS, Poznán, Poland.
authors.forename: W
authors.initials: W
authors.lastname: Medycki
mesh_terms: D002412:Cations; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008744:Methylamines; D011522:Protons
chemical_list: D002412:Cations; D008744:Methylamines; D011522:Protons; C027451:methylamine