2007/09/19 by E. Kusano, Eiji Kusano, S. Kawasaki +6
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Hydrostatic pressure #Magnetic and transport properties of perovskites and related materials #Physics #Physics of Superconductivity and Magnetism #Superconductivity #Thermodynamics #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.76.100506
published as Phys. Rev. B76, 100506(R) (2007) · published on 19, Sept. 2007 on Phys. Rev. B
openalex publication_date 2007/09/19 · arxiv created 2007/12/04 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report Tc and 59Co nuclear quadrupole resonance measurements on the cobalt oxide superconductor NaxCoO2∙1.3H2O (Tc=4.8\phantom\rule0.3em0exK) under hydrostatic pressure (P) up to 2.36\phantom\rule0.3em0exGPa. Tc decreases with increasing pressure at an average rate of \ensuremath-0.49\ifmmode±\else\textpm\fi0.09\phantom\rule0.3em0exK∕GPa. At low pressures P\ensuremath\leqslant0.49\phantom\rule0.3em0exGPa, the decrease of Tc is accompanied by a weakening of the spin correlations at a finite wave vector and a reduction of the density of states (DOS) at the Fermi level. At high pressures above 1.93\phantom\rule0.3em0exGPa, however, the decrease of Tc is mainly due to a reduction of the DOS. These results indicate that the electronic and magnetic state of Co is primarily responsible for the superconductivity. The spin-lattice relaxation rate 1∕T1 at P=0.49\phantom\rule0.3em0exGPa shows a T3 variation below Tc down to T\ensuremath∼0.12Tc, which provides compelling evidence for the presence of line nodes in the superconducting gap function.