Effects of Mn and Ti doping on superconductivity and charge ordering in NaxCoO2 system

TL;DR

This study investigates how Mn and Ti doping affect superconductivity and charge ordering in Na_xCoO_2 compounds, revealing suppression of superconductivity at low doping levels and changes in charge ordering and magnetic properties.

Contribution

It provides systematic synthesis and analysis of Mn and Ti doped Na_xCoO_2 compounds, demonstrating their impact on superconductivity and charge ordering phenomena.

Findings

Superconductivity is suppressed at x=0.02 for Mn and x=0.01 for Ti doping.

Lattice parameters vary systematically with doping levels.

Charge ordering and magnetic properties are influenced by M-atom doping.

Abstract

The superconductivity in Na0.3Co1-xMxO2.1.3H2O and the charge ordering in Na0.5Co1-xMxO2 have been investigated for M = Mn and Ti substituting for Co. We have first successfully synthesized the single-phase Na0.7Co1-xMxO2(M= Mn and Ti) materials with 0 < = x < = 0.1, then we obtained Na0.5Co1-xMxO2 (0 < = x < = 0.1, M = Mn and Ti) by Na deintercalation and Na0.3Co1-xMxO2.1.3H2O (0 < = x < = 0.1, M = Mn and Ti) by an additional water intercalations. X-ray diffraction measurements revealed that all samples are single-phase materials, their lattice parameters depend systematically on the Ti and Mn contents. Measurements of physical properties indicate that the superconductivity in Na0.3Co1-xMxO2.1.3H2O is suppressed evidently by Co-site doping and killed at x = 0.02 for Mn doping and x = 0.01 for Ti doping. Charge ordering and magnetic properties in Na0.5Co1-xMxO2 were also influenced by M-atom doping.