Alteration of negative lattice expansion of the La(Fe,Si)13-type phase in LaFe11.14−xCo0.66NixSi1.2 alloys

Inthe present work the temperature dependence of lattice parameters and magnetic properties of the LaFe11.14−xCo0.66NixSi1.2 (where x=0.1,0.2,0.3) alloys were investigated. X-ray diffraction studies of all specimens revealed coexistence of two crystalline phases: the dominant La(Fe, Si)13-type phase and minor fraction of bcc α-Fe. Furthermore changes in negative lattice expansion with the increase of Ni content in the alloy composition were also shown. The increase of Ni content caused rise of the Curie temperature and decrease of the amplitude of magnetic entropy changes.