X-ray diffraction and magnetic properties of beta-Mn1-xOsx alloys

The X-ray powder diffraction patterns of Mn1-xOsx (x less than or equal to 0.36) alloys quenched from 1123 K show the beta-Mn structure in which Os at oms preferentially occupy site 1, whereas the patterns of the specimens que nched from 873 K exhibit the alpha-Mn structure below x = 0.14. Using the r esultant data, we have determined the phase diagram of the Mn-Os alloy syst em for the first time. The Neel temperature of beta-Mn1-xOsx (x less than o r equal to 0.36) alloys determined from the magnetic susceptibility increas es with increasing Os concentration. The electronic specific heat coefficie nt, gamma, of samples with relatively low Os concentration is considerably large due to spin fluctuations. (C) 2000 Elsevier Science S.A. All rights r eserved.