Pressure effects on magnetic properties and electronic structure of EuB6 and GdB6

Highlights: → We studied pressure effect on magnetic susceptibility of EuB6 and GdB6. → Strong positive pressure effect on paramagnetic Curie temperature is found in EuB6. → In GdB6 and carbon doped EuB6 the effect is lower and opposite in sign. → Ab initio based RKKY-like approach explains pressure effects on magnetic ordering. - Abstract: Experimental and theoretical studies of the pressure effects on magnetic properties and electronic structure of EuB6 and GdB6 compounds were carried out to shed light on the nature of their magnetic ordering. The magnetic susceptibility was measured under pressure up to 2 kbar at fixed temperatures of 78 and 300 K for the EuB6 and GdB6 compounds, and also for the carbon doped EuB6, for comparison. The observed behavior of the paramagnetic Curie temperature Θ under pressure was analyzed within the RKKY-like approach based on the results of ab initio electronic structure calculations.