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27Al and 63Cu NMR studies on intermetallic Kondo compound CeCu3Al2
B. Bandyopadhyay, A. Ghoshray, K. Ghoshray
Published in
2010
Volume: 405

Issue: 22
Pages: 4691 - 4695
Abstract
Detailed 27Al and 63Cu nuclear magnetic resonance (NMR) experiments have been performed in between 4.5 and 295 K on a polycrystalline sample of CeCu3Al2 which has a Kondo temperature ∼11K. The NMR spectral features and Knight shift measurements show that in this compound, Cu occupy both c and g lattice sites, while Al occupy only the g sites. From the temperature dependence of Knight shift (K), the hyperfine fields for 63Cu and 27Al at the g sites have been estimated as 2.02(5) and 1.67(5)kOe/$\mu$B, respectively and that for 63Cu at c sites as -3.83(5)kOe/$\mu$B. Nuclear spin-lattice relaxation time (T1) measurements indicate that though the relaxation process is governed by fluctuations of magnetic interaction, nuclear quadrupolar interaction also has a significant contribution, especially towards relaxation of 63Cu in both c and g sites. For 27Al, K and T 1 have yielded the effective 4f-spin correlation rate 1/$\tau$4f. The behavior of its temperature dependence indicates that at low temperatures in CeCu3Al2, the valence state of cerium might not be stable. {\textcopyright} 2010 Elsevier B.V. All rights reserved.