59Co-NQR study on superconducting NaxCoO2.yH2O

Abstract

Layered Co oxide NaxCoO2.yH2O with a superconducting transition temperature Tc =4.5 K has been studied by 59Co NQR. The nuclear spin relaxation rate 1/59T1 is nearly proportional to temperature T in the normal state. In the superconducting state, it exhibits the coherence peak and decreases with decreasing T below ~0.8Tc. Detailed comparison of the 1/T1T values and the magnetic susceptibilities between NaxCoO2.yH2O and NaxCoO2 implies that the metallic state of the former system is closer to a ferromagnetic phase than that of the latter. These experimental results impose a restriction on the mechanism of the superconductivity.

7 pages, 5 figures. to be published in J. Phys. Soc. Jpn. 72 (2003) No.9

References in corpus (2)

• Unconventional magnetic transition and transport behavior in Na0.75CoO2
• Transport and Magnetic Properties of R1-xAxCoO3 (R=La, Pr and Nd; A=Ba, Sr and Ca)

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