Persistence of local-moment antiferromagnetic order in Ba(1-x)KxMn2As2

BaMn2As2 is a local-moment antiferromagnetic insulator with a N\'eel temperature of 625 K and a large ordered moment of 3.9 Bohr magneton per Mn. Remarkably, this compound can be driven metallic by the substitution of as little as 1.6% K for Ba while retaining essentially the same ordered magnetic moment and N\'eel temperature, as previously reported. Here, using both powder and single crystal neutron diffraction we show that the local moment antiferromagnetic order in Ba(1-x)KxMn2As2 remains robust up to x = 0.4. The ordered moment is nearly independent of x for 0 < x < 0.4 and the N\'eel transition temperature decreases to 480 K at x = 0.4.