Calorimetric Studies of Phase Transformations in the La1 – xYxMn2Si2 System

Differential scanning calorimetry (DSC) is used to determine the magnetic phase transformation temperatures of the La 1 – x Y x Mn 2 Si 2 ( x = 0–1) alloys. For the compositions with х from 0 to 0.3, the temperature dependences of DSC signal exhibit λ-like endothermic effects observed near 300 K, which are related to the magnetic phase transition from the ferromagnetic to layered antiferromagnetic structure, and weak anomalies, which are observed in a temperature range of from 458 K for the composition with х = 0 to 323 К for the composition with х = 0.3 upon disordering of the layered antiferromagnetic structure. A clear endothermic peak corresponding to the disordering of interplane antiferromagnetic layered structure was found for the YMn 2 Si 2 . The data obtained are used to construct the magnetic phase diagram of the La 1 – x Y x Mn 2 Si 2 system in a temperature range of 270–600 К. The differential scanning calorimetry is shown can be successfully used for the determination of temperatures of various magnetic phase transformations in rare-earth intermetallic compounds.