Local moments and symmetry breaking in metallic PrMnSbO

Kimber SAJ, Hill AH, Zhang Y-Z, Jeschke HO, Valentí R, Ritter C, Schellenberg I, Hermes W, Pöttgen R, Argyriou DN

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 liquidlike T2 behavior below 150 K. Neutron powder diffraction shows that unfrustrated C-type Mn magnetic order develops below ∼230 K, followed by a spin flop coupled to induced Pr order. At T∼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.