Local moments and symmetry breaking in metallic PrMnSbO

TL;DR

This study combines experimental and theoretical methods to investigate PrMnSbO, revealing local magnetic moments, magnetic ordering, and a structural transition driven by f-electron effects, contrasting with models for iron pnictides.

Contribution

It provides the first detailed analysis of PrMnSbO, showing that its structural distortions are driven by f-electron degrees of freedom, unlike iron pnictides.

Findings

Unfrustrated C-type Mn magnetic order develops below 230 K.

A tetragonal to orthorhombic transition occurs around 35 K.

Large magnetic moments are of local origin, not itinerant.

Abstract

We report a combined experimental and theoretical investigation of the layered antimonide PrMnSbO which is isostructural to the parent phase of the iron pnictide superconductors. We find linear resistivity near room temperature and Fermi liquid-like T^{2} behaviour below 150 K. Neutron powder diffraction shows that unfrustrated C-type Mn magnetic order develops below \sim 230 K, followed by a spin-flop coupled to induced Pr order. At T \sim 35 K, we find a tetragonal to orthorhombic (T-O) transition. First principles calculations show that the large magnetic moments observed in this metallic compound are of local origin. Our results are thus inconsistent with either the itinerant or frustrated models proposed for symmetry breaking in the iron pnictides. We show that PrMnSbO is instead a rare example of a metal where structural distortions are driven by f-electron degrees of freedom.