Nuclear-Magnetic-Resonance Properties of the Staircase Kagomé Antiferromagnet PbCu3TeO7.

We report the first nuclear magnetic resonance (NMR) study on single crystals of staircase Kagomé antiferromagnet PbCu3TeO7 (TN1 ∼36 K). A Curie constant Θ ∼ −140 K is obtained by a Curie–Weiss fit to the high-temperature Knight shift of 125Te. The hyperfine coupling constant is estimated to be 125Ahf = −67 kOe/μB, and a strong interlayer coupling among staircase Kagomé planes is suggested with such a large hyperfine coupling, according to the lattice structure. The 63,65Cu NMR spectra are found by the zero-field (ZF) NMR at T = 2 K, and the internal hyperfine fields are estimated to be 10.3 T and 9.6 T, for Cu(1) and Cu(2) sites, respectively, in the lattice. A second type of ZF NMR signal with a large rf enhancement is also seen after field-cycling through a high magnetic field. [ABSTRACT FROM AUTHOR]