Investigation of the New P′3‐Na0.60VO2 Phase: Structural and Physical Properties.

A new layered phase Na0.60VO2 was synthesized by chemical deintercalation of sodium from the pristine compound O3-NaVO2. The Na0.60VO2 compound exhibits a distorted P′3-type oxygen stacking (AABBCC) with an average monoclinic unit cell containing a = 4.9862(14) A, b = 2.8708(8) A, c = 5.917(2) A, and β = 104.36(3)°. A modulated structure was observed by transmission electron microscopy and X-ray diffraction (XRD) measurements. Indexation of the XRD pattern was achieved by using the q vector equal to 0.44b*, and the 4D superspace group C2/m (0 β 0) s0 was then deduced. The specific heat measurement showed a strong correlated system with a γ value of around 20 mJ·mol−1·K−2. The electrical conductivity shows a semiconductor-like behavior with an activation energy of 0.52 eV. A paramagnetic behavior of the susceptibility is observed below room temperature with a Curie constant equal to C = 0.076 emu·K−1·mol−1·Oe−1. To explain this small value, a model of pseudotriangular clusters of vanadium with a random dis...