NMR Study on (CH 3 ) 2 NH 2 H 2 AsO 4 |
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Authors: | Junko Hatori Yasumitsu Matsuo Masaru Komukae Seiichiro Ikehata Toshio Osaka |
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Affiliation: | a Department of Applied Physics, Faculty of Science, Science University of Tokyo, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601. |
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Abstract: | Proton NMR line width and spin-lattice relaxation time T 1 for the ferroelectric (CH 3 ) 2 NH 2 H 2 AsO 4 have been measured at the temperature range between 77 K and 300 K. The temperature dependence of T 1 is well described by the expressions based on rotation of the methyl group using the value of activation energy E a = 99 meV and elementary correlation time τ0 = 1.5 ×10 -13 sec. Moreover, a sharp dip of T 1 near ferrroelectric phase transition temperature ( T c = 274.5 K) results from the ordering of protons. In addition, the temperature dependence of T 1 deviates from the expression for molecular rotation above around 200 K. It is deduced that the deviation is caused by the suppression of some kind of proton motion. |
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Keywords: | (CH 3 ) 2 NH 2 H 2 AsO 4 Nmr Proton Dynamics |
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