Magnetic characterization of Mn5SiB2 and Mn5Si3 phases

In this work the Mn5Si3 and Mn5SiB2 phases were produced via arc melting and heat treatment at 1000 deg. C for 50 h under argon. A detailed microstructure characterization indicated the formation of single-phase Mn5Si3 and near single-phase Mn5SiB2 microstructures. The magnetic behavior of the Mn5Si3 phase was investigated and the results are in agreement with previous data from the literature, which indicates the existence of two anti-ferromagnetic structures for temperatures below 98 K. The Mn5SiB2 phase shows a ferromagnetic behavior presenting a saturation magnetization Ms of about 5.35x105 A/m (0.67 T) at room temperature and an estimated Curie temperature between 470 and 490 K. In addition, AC susceptibility data indicates no evidence of any other magnetic ordering in 4-300 K temperature range. The magnetization values are smaller than that calculated using the magnetic moment from previous literature NMR results. This result suggests a probable ferrimagnetic arrangement of the Mn moments.