Nuclear spin-lattice relaxation of thulium in TmBa2Cu3O6+x at low temperatures
Bakharev O. N. , Volodin A. G. , Duglav A. V. , Egorov A. V., Marvin O. B., Naletov V. V. , Teplov M. A. , Wagner D.
"Amplified NMR" of thulium has been utilized to determine the positions of the paramagnetic Cu2+ centers in the crystal lattice of TmBa2Cu306+x (x = 0-l). Analysis of the measured rate of spin-lattice relaxation of thulium nuclei in oriented TmBaCuO powders at low temperatures (to 40 mK) shows that in superconducting compounds (jc=0.4—1.0) the paramagnetic copper centers are localized at walls between superconducting and nonsuperconducting microdomains. The average length of the segments of the CuO chains is estimated (—90 A at x= 1.0). The density of the paramagnetic Cu2+(2) centers is also estimated (2.4X1019 cm"3 at x=1.0).
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![](/ps/1191/article_17980_800_head.png ""Amplified NMR" of thulium has been utilized to determine the positions of the paramagnetic Cu<sup>2+</sup> centers in the crystal lattice of TmBa<sub>2</sub>Cu<sub>3</sub>0<sub>6+x </sub>(x = 0-l). Analysis of the measured rate of spin-lattice relaxation of thulium nuclei in oriented TmBaCuO powders at low temperatures (to 40 mK) shows that in superconducting compounds (<b>jc</b>=0.4—1.0) the paramagnetic copper centers are localized at walls between superconducting and nonsuperconducting microdomains. The average length of the segments of the CuO chains is estimated (—90 A at <b><i>x= </i></b>1.0). The density of the paramagnetic Cu<sup>2+</sup>(2) centers is also estimated (2.4X10<sup>19</sup> cm"<sup>3</sup> at x=1.0).")