Phase gap in pseudoternary R1-yRy Mn2X 2-xXx compounds

site which in turn produces subtle variations in the local lattice andabrupt changes in the Mn-Mn magnetic exchange interaction. Our results show that coexistence of Fmc andAFmc phases depends on lattice parameter, chemical pressure from the rare-earth and metalloid sites, and locallattice strain distributions. We demonstrate that these magnetostructural correlations act across the entire familyof