Absence of itinerant ferromagnetism in a cobalt-based oxypnictide

TL;DR

This study synthesizes a new layered oxypnictide, revealing no itinerant ferromagnetism in CoAs layers, highlighting the importance of Co-Co bond length in magnetic properties.

Contribution

The paper reports the synthesis and characterization of a novel Sr2CrCoAsO3 oxypnictide, providing insights into its magnetic behavior and the role of Co-Co bond length in ferromagnetism.

Findings

No itinerant ferromagnetism observed in CoAs layers

Metallic conductivity confirmed in the material

Short-range antiferromagnetic ordering in CrO2 planes

Abstract

We report a layered transition-metal-ordered oxypnictide Sr$_{2}$CrCoAsO$_{3}$. The new material was synthesized by solid-state reactions under vacuum. It has an intergrowth structure with a perovskite-like Sr$_3$Cr$_2$O$_6$ unit and ThCr$_2$Si$_2$-type SrCo$_2$As$_2$ block stacking coherently along the crystallographic $c$ axis. The measurements of electrical resistivity, magnetic susceptibility, and specific heat indicate metallic conductivity from the CoAs layers and short-range antiferromagnetic ordering in the CrO$_{2}$ planes. No itinerant-electron ferromagnetism expected in CoAs layers is observed. This result, combined with the first-principles calculations and the previous reports of other CoAs-layer-based materials, suggests that the Co$-$Co bondlength plays a crucial role in the emergence of itinerant ferromagnetism.