Vyaselev O, Arai K, Kobayashi K, Yamazaki J, Kodama K, Takigawa M, Hanawa M, Hiroi Z
Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
Phys Rev Lett. 2002 Jul 1;89(1):017001. doi: 10.1103/PhysRevLett.89.017001. Epub 2002 Jun 13.
We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K.
我们报道了对Cd₂Re₂O₇（焦绿石氧化物中的首个超导体，Tc约为1 K）的镉核磁共振（NMR）和铼核四极共振（NQR）研究。在100 K以下的零磁场中，铼NQR谱排除了任何磁序或电荷序。低于Tc时的自旋 - 晶格弛豫率呈现出明显的相干峰，并且遵循具有近乎各向同性能隙的弱耦合BCS理论。镉NMR的结果表明，在高温下有适度的铁磁增强，随后在200 K的结构转变温度以下态密度迅速下降。
