Magnetic properties of the Laves-type phases Ti₂Co₃Si and Ti₂Fe₃Si and their solid solution

Interest in Fe and Co containing Laves-type phases arises from their promising magnetic properties, especially in the context of magnetostrictive and magnetocaloric materials. Most compounds that are used for these applications consist of rare earth elements that are economically and environmentally problematic. Ti₂Co₃Si and Ti₂Fe₃Si are therefore attractive rare earth-free candidates, however their magnetic behavior has not been studied in full detail yet. Consequentially, we have prepared the full solid solution between both phases by arc melting and spark plasma sintering. The samples were subject to comprehensive investigation by means of synchrotron X-ray diffraction, EDX analysis and SQUID measurements. The magnetic properties of the mostly single phase materials generally follow a clear trend with an increase in the magnetic moment with increasing Fe content. Interestingly, we found a sudden drop in magnetic moment between samples Ti₂Fe₃Si and Ti₂(Co_0.2Fe_0.8)₃Si. This phase transition from the ferromagnetic to the antiferromagnetic configuration for these compositions can indeed be confirmed by theoretical calculations.