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NMR Investigation of the Organic Conductor lambda-(BETS)2FeCl4

W. G. Clark·Guoqing Wu·P. Ranin·L. K. Montgomery·L. Balicas
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Abstract

The two-dimensional organic conductor lambda-(BETS)2FeCl4 has an unusual phase diagram as a function of temperature and magnetic field that includes a paramagnetic metal (PM) phase, an antiferromagnetic insulating (AFI) phase, and a field-induced superconducting phase [S. Uji, H. Kobayashi, L. Balicas, and James S. Brooks, Adv. Mater. 14, 243 (2002), and cited references]. Here, we report a preliminary investigation of the PM and AFI phases at 9.0 T over the temperature range 2.0-180 K that uses proton NMR measurements of the spectrum, the spin-lattice relaxation rate (1/T1), and the spin echo decay rate (1/T2). The sample is asmall single crystal whose mass is approximately 3 micrograms (approximately 2E16 protons). Its small size creates several challenges that include detecting small signals and excluding parasitic proton signals that are not from the sample [H. N. Bachman and I. F. Silvera, J. Mag. Res. 162, 417 (2003)]. These strategies and other techniques used to obtain viable signals are described.

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W. G. Clark, Guoqing Wu, P. Ranin, L. K. Montgomery, L. Balicas. 2003-10-18. NMR Investigation of the Organic Conductor lambda-(BETS)2FeCl4. https://arxiv.org/abs/cond-mat/0310433

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