Filling the holes in the CaFe${}_4$As${}_3$ structure: synthesis and magnetism of CaCo${}_5$As${}_3$

Abstract

Here we investigate single crystals of CaCo${}_5$As${}_3$ by means of single crystal X-ray diffraction, microprobe, magnetic susceptibility, heat capacity, and pressure-dependent transport measurements. CaCo${}_5$As${}_3$ shares the same structure of CaFe${}_4$As${}_3$ with an additional Co atom filling a lattice vacancy and undergoes a magnetic transition at $T_M=16$ K associated with a frustrated magnetic order. CaCo${}_5$As${}_3$ displays metallic behavior and its Sommerfeld coefficient ($\gamma =70$ mJ/mol.K${}^2$) indicates a moderate enhancement of electron-electron correlations. Transport data under pressures to $2.5$ GPa reveal a suppression of $T_M$ at a rate of $-0.008$ K/GPa. First-principle electronic structure calculations show a complex 3D band structure and magnetic moments that depend on the local environment at each Co site. Our results are compared with previous data on CaFe${}_4$As${}_3$ and provide a scenario for a magnetically frustrated ground state in this family of compounds.

References in corpus (3)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Incommensurate magnetic order in the alpha-Fe(Te,Se) superconductor systems