From the 17O Knight shift measurements on O(1) in RuO2 planes and O(2) in SrO layers in Sr2RuO4 with Tc = 1.5 K, it is shown that the distribution of the spin density at the O(1) sites reflects two-dimensional electronic structure with most of its fraction on the in-plane pπ orbitals. From systematic measurements of the nuclear spin-lattice relaxation rate, T1-1, it is found that dynamical susceptibility is highly anisotropic in contrast to the uniform susceptibility being isotropic. Their in-plane components for the O(1) sites are almost independent of wavenumber although they are exchange-enhanced, whereas it is unexpected that the out-of-plane component being q dependent is pronouncedly enhanced by interlayer antiferromagnetic spin fluctuations below T* ∼ 130 K where the c-axis resistivity shows a metallic behavior. These novel characters of spin fluctuations are suggested to lead to discussions about a possible mechanism of spin-triplet p-wave superconductivity in Sr2RuO4.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering