Abstract
In the neodymium-manganese intermetallics, Nd6Mn23 is the only one that shows ferromagnetic. The crystal structure of Nd6Mn23 is F.C.C., and the space group is F/m3m. The 225 atoms compose Nd6Mn23, so the crystal is very complex. In this study, carbon or boron was added into Nd6Mn23 to explore it's effecte. In the experimental results, the crystal structure is distorted slightly. As the concentration of boron in the Nd6Mn23 alloy increases, the peaks of the Nd6Mn23 X-ray pattern enhance. But carbon doesn't have the same effect. In the Nd6Mn23 alloy, if the concentration of carbon increases, the Nd6Mn23 tend to be decomposed to NdMn2. The magnetic measurement showed that the boron addition in the Nd6Mn23 alloy decreases the magnetic moment first and then increases it again to the maximum. The carbon addition in the Nd6Mn23 alloy has the same situation. The change in the Curie temperature(TC) has the same tendency. There exits a maximum temperature. In the boron added case, the maximum(TC) temperature is 448K(12.12 at.%B); in the carbon added case, the maximum temperature is 444K(6.45 at.%C). The variation in magnetic properties may be due to the manganese atom's distance. The Mn-Mn distances ranges is from 2.5A to 3.02 A. If the distance is less than 2.8 A, the Mn-Mn magnetic interaction are generally antiferomagnetic. So, the carbon or the boron addition in the Nd6Mn23 alloy, may change the distance, and the magnetic property and Curie temperature are varied.