Instability and evolution of the magnetic ground state in metallic perovskites GdRh${}_3$C${}_{1-x}$B${}_x$

Abstract

We report investigations of the structural, magnetic, electrical transport and thermal properties of five compositions of the metallic perovskite GdRh${}_3$C${}_{1-x}$B${}_x$ ($0.00\le x\le 1.00$). Our results show that all the five compositions undergo magnetic ordering at low temperatures, but the nature of the ordered state is significantly different in the carbon- and the boron-rich compositions, where the former shows signatures of an amplitude-modulated magnetic structure and the latter exhibits evidences of an equal-moment incommensurate antiferromagnetic ordering. We also observe a remarkable field-dependent evolution of conduction carrier polarization in the compositionally disordered compounds. The outcomes indicate that this system is energetically situated in proximity to a magnetic instability where small variations in the control parameter(s), such as lattice constant and/or electron density, lead to considerably different ground states.

10 pages and 9 figures