Magnetoelastic Properties of the MnRuxRh1-x As system: Crystal, Electronic Structure and Magnetocaloric Effect Analyses

The crystal structure of MnRu
_x
Rh
_1-x
As system belongs to the hexagonal Fe
₂
P-type structure (SG: P 6 2m). Mn atoms locate at pyramidal (3g) sites, Ru and Rh atoms occupy tetrahedral (3f) sites and As atoms occupy 1b and 2c positions. Systematic XRD data collected in the 80 - 550 K temperature range and crystal structure refinements were performed for 0.05 <; x <; 1. From the thermal behavior of both the cell parameters and the atomic positions, a global analysis of the magneto-elastic characteristics was made. In this report we present the magnetocaloric characteristics (MCE), addressed to the Mn magnetic ordering. Both conventional (0.8<; x<; 1) and negative MCE (0 <; x <; 0.75) were pointed out. Besides to analyze the magnetization behavior of the compounds for 0.8 <; x <; 1, a mean-field approach was applied successfully. Finally, relationships were established between experimental and theoretical values of the magnetic moments and the different types of magnetic couplings.