NMR study of naturally occurringC13in the Haldane-gap material Ni(C2H8N2)2NO2ClO4
| Autor: | A. P. Reyes, Naoki Fujiwara, William P Halperin, H. N. Bachman, M. W. Meisel, X. P. Tang, Takuya Goto |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Physical Review B. 55:8079-8082 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.55.8079 |
| Popis: | The spin-lattice relaxation time ${\mathrm{T}}_{1}$ of naturally occurring $^{13}\mathrm{C}$ in Ni(${\mathrm{C}}_{2}$${\mathrm{H}}_{8}$${\mathrm{N}}_{2}$${)}_{2}$${\mathrm{NO}}_{2}$${\mathrm{ClO}}_{4}$, a Haldane-gap system commonly known as NENP, has been measured as a function of temperature (Tg4 K), magnetic field (H=3.46 and 7.56 T), and crystal orientation [a, b (the Ni chains), and c axes]. Using the established magnetic-field dependence of the gap and the materials parameters known for NENP, the general trends of the ${\mathrm{T}}_{1}$ data can be reproduced by standard analysis with the assumption that the relaxation is governed by the processes at q=\ensuremath{\pi}. Most importantly, an unusual feature in the H(\ensuremath{\parallel}b)=7.56 T data can only be explained by using a temperature-dependent gap. |
| Databáze: | OpenAIRE |
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