X-ray and Mössbauer studies of the Tb$_{0.3}$Dy$_{0.7}$Fe$_{2-x}$Co$_x$ system alloys

A complex study of the phase composition, atomic and crystalline structure, magnetic properties, and superfine interactions of the Tb$_{0.3}$Dy$_{0.7}$Fe$_{2-x}$Co$_x$ system alloys (${x=0}$-1.3) has been performed. The synthesized alloys are isotypic with the cubic Laves phase (C15 type), their cell parameter monotonically decreases with an increase in the Co content and, hence, the saturation magnetostriction also does. However, the concentration dependences of the Curie temperature, saturation magnetization, and superfine magnetic field strength measured in the Mössbauer experiment display a nonmonotonic (dome-like) character.