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 GdRh3C1−xBx (0.00 ≤ x ≤ 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.