Effect of Magnetic Field Annealing on the Magnetic Properties of Soft-Magnetic Iron–Germanium Alloys

—A concentration dependence of the magnetic properties of iron–germanium alloys is studied before and after their thermomagnetic treatment, which includes the annealing of samples in the ferromagnetic state in dc and ac magnetic fields (magnetic field annealing (MFA)). It is shown that, before MFA, as the germanium content increases in a range of 3–30 at %, the coercive force increases, whereas the remanence decreases. The magnetic anisotropy is induced in the alloy samples as a result of the MFA; in this case, the magnetic hysteresis loops become narrower, the remanence increases, and the coercive force decreases. The MFA is efficient for the Fe–Ge alloys with 6 to 18 at % germanium; in this case, the highest efficiency takes place at a germanium content of 12 at %. Peculiarities of the structural state of the iron–germanium alloys and their role in the formation of magnetic properties in the course of MFA are discussed.