Suppression of spin density wave by isoelectronic substitution in PrFe(1-x)Ru(x)AsO

TL;DR

This study investigates how substituting Ru for Fe in PrFeAsO suppresses the spin density wave and affects magnetic order, revealing that larger Ru orbitals disrupt magnetism without inducing superconductivity.

Contribution

It provides experimental and theoretical insights into how isoelectronic Ru substitution suppresses SDW and magnetic order in PrFeAsO, highlighting the role of orbital size and structural distortion.

Findings

SDW is completely suppressed with Ru substitution

Pr magnetic order is suppressed at low Ru concentrations

No superconductivity observed above 2 K

Abstract

We have studied the effects of the isoelectronic substitution of Ru for Fe in polycrystalline samples of the spin density wave (SDW) material PrFeAsO. Crystal structures from powder x-ray diffraction at room temperature and transport properties from 2-300 K are reported. The SDW is completely suppressed upon Ru substitution. The distortion of the tetrahedral coordination environment of the transition metal site increases as the Ru concentration increases, which may be related to the absence of superconductivity above 2 K. Band structure calculations show that the larger size of Ru 4$d$ orbitals is primarily responsible for the suppression of magnetism as Ru is substituted into the Fe layer. The experimental results indicate that long-ranged magnetic order of Pr moments is suppressed at Ru concentrations as low as 10%.