Correlation between Tc and Lattice Parameters of Novel Superconducting NaxCoO2 yH2O

TL;DR

This study investigates the relationship between the superconducting transition temperature and lattice parameters in novel Na-based cobalt oxide superconductors, revealing a correlation that could inform future material design.

Contribution

It reports the synthesis and structural analysis of new P3 type Na$_{x}$(H$_{3}$O)$_{y'}$CoO$_{2}ullet y''$H$_{2}$O superconductors and establishes a correlation between $T_{c}$ and lattice parameters.

Findings

$T_{c}$ varies from 4.6 K to 3.2 K across batches.

Lattice parameters are well correlated with $T_{c}$.

Magnetic susceptibility shows low-temperature upturn similar to P2 phase.

Abstract

We synthesized the five batches of the samples of the novel P3 type superconductor, Na$_{x}$(H$_{3}$O)$_{y'}$CoO$_{2}\cdot y''$H$_{2}$O, by the soft chemical process starting from $\alpha$-NaCoO$_{2}$. The chemical and structural properties varied rather widely from batch to batch, with a result that $T_{c}$ varied from 4.6 K to 3.2 K. The magnetic susceptibility above $T_{c}$ shows upturn at low temperature as in the case of the P2 phase. The $T_{c}$ seems to be well correlated to the lattice parameters.