Temperature Dependence of Structural and Magnetic Transformations in Finemet-type Amorphous Alloys with Fe Substituted for La

Structural and magnetic properties of amorphous and partly crystallized $$\text {Fe}_{73.5-{\text{x}}}\text {La}_{\text{x}=0,1,3,5,7}\text {Si}_{13.5}\text {B}_{9}\text {Nb}_{3}\text {Cu}_{1}$$ alloys were analysed in the temperature ranging from room temperature (RT) to 800 $$^\circ $$ C with differential scanning calorimetry (DSC) and thermomagnetic gravimetry (TMG). The Fe(Si) and Fe(B) structures were identified and characterized with set of crystallization temperatures and activation energies. Also, Curie temperatures for amorphous and for crystalline structures were determined and analysed as functions of La content.