59Co NMR study on local magnetic properties of Ca1−xNaxCo2O4

59Co NMR measurements have been performed to study the local magnetic properties of Ca1−xNaxCo2O4 with x = 0-0.6, which is a new system synthesized for the first time under a high pressure. The Knight shift of the 59Co NMR spectra for these materials is small and almost T-independent even when the Ca ions are substituted by Na up to x = 0.6. Furthermore, a magnetic order is not observed at least down to 4.2 K for the samples with x = 0-0.6 prepared in this work. In order to explain these peculiar magnetic behaviors, site-selective distribution of holes has been discussed.