Affiliation: | Ottawa-Carleton Institute for Physics, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5 Centro de Estudios en Semiconductores, Departamento de Física, Universidad de Los Andes, Mérida, Venezuela |
Abstract: | Measurements of magnetic susceptibility in the temperature range 4.2–300 K were made on polycrystalline samples of the (AgIn)1 - zMn2zTe2 and (CuIn)1 - zMn2zTe2 alloys, and the data used to give values of spin-glass transition te mperature Tg and Curie-Weiss paramagnetic temperature θ. For any sample for which the X-ray powder photograph indicated an apparently single phase condition, either zinc-blende or chalcopyrite, the susceptibility data could show up to three separate Tg values. These different magnetic conditions are attributed to crystallographic ordering of the Mn ions on the chalcopyrite and zinc-blende lattices, the three observed Tg values corresponding to disordered zinc-blende, ordered zinc-blende and ordered chalcopyrite. The value of θ obtained from the 1/χ vs. T plot is shown to be a weighted mean of the separate values of θ for the phases present. The relative sizes of the Tg peaks and the values of θ for any given sample gives an indication of the amount of each phase present. These amounts were varied by using different methods of heat treatment and it was shown that the magnetic behaviour was consistent with the T(z) phase diagram for the two alloy systems. |