Magnetic properties of undercooled Co-based alloys

Co-based melts in a glass flux can be undercooled nearly as strong as samples processed containerless by electromagnetic levitation. The undercooling technique is combined with the use of a Faraday-balance to measure magnetic susceptibility on highly undercooled melts. The magnetic susceptibility of Co and Co–Au is investigated as a function of temperature from stable liquid to undercooled liquid state using a Faraday-balance. When liquid Co-based alloys are undercooled the magnetisation steeply rises when temperature approaches the Curie temperature. The magnetisation is presented for Co and Co90Au10 in solid and liquid state as a function of temperature. The results show that the magnetic susceptibility of the liquid undercooled samples follows a Curie–Weiss behaviour, from which Curie temperature and magnetic moment are inferred. In no case an undercooling below the Curie temperature was achieved.