Method for producing a soft-magnetic alloy, having: the provision of a precursor having a composition substantially consisting of 2 % w/w ≤ Co ≤ 30 % w/w 0.3 % w/w ≤ V ≤ 5.0 % w/w 0 % w/w ≤ Cr ≤ 3.0 % w/w 0 % w/w ≤ Si ≤ 5.0 % w/w 0 % w/w ≤ Mn ≤ 5.0 % w/w 0 % w/w ≤ Al ≤ 3.0 % w/w 0 % w/w ≤ Ta ≤ 0.5 % w/w 0 % w/w ≤ Ni ≤ 1.0 % w/w 0 % w/w ≤ Mo ≤ 0.5 % w/w 0% w/w ≤ Cu ≤ 0.2 % w/w 0 % w/w ≤ Nb ≤ 0.25 % w/w 0 % w/w ≤ Ti ≤ 0.05 % w/w 0 % w/w ≤ Ce ≤ 0.05 % w/w 0 % w/w ≤ Ca ≤ 0.05 % w/w 0 % w/w ≤ Mg ≤ 0.05 % w/w 0 % w/w ≤ C ≤ 0.02 % w/w 0 % w/w ≤ Zr ≤ 0.1 % w/w 0 % w/w ≤ O ≤ 0.025 % w/w 0 % w/w ≤ S ≤ 0.015 % w/w rest iron and up to 0.2 % w/w melting-related impurities, wherein the precursor has a phase transition from a BCC phase area into a BCC/FCC mixed area to an FCC phase area, wherein at increasing temperature the phase transition between the BCC phase area and the BCC/FCC mixed area occurs at a first transition temperature T α/α+γ and at further increasing temperature the transition between the BCC/FCC mixed area and the FCC phase area occurs at a second transition temperature T α+γ/γ and the difference T α+γ/γ - T α/α+γ is less than 45 K, preferably less than 25 K, the partial coating of the precursor with a ceramic-forming layer, wherein the precursor has the form of a sheet with a first surface and a second, opposite surface, wherein at least between 20% and 80%, preferably between 30% and 70%, particularly preferred between 50% and 70% of the first surface and between 20% and 80%, preferably between 30% and 70%, particularly preferred between 50% and 70% of the second surface remain free of the ceramic-forming layer, the heat treatment of the partially coated precursor, wherein the heat treatment comprises the heating of the precursor, and then the heat treatment of the precursor in a first stage with a total time t 1, wherein in the first stage the precursor is heat-treated at a temperature in a temperature range between T α+γ/γ and T 1, and then the cooling of the precursor to room temperature, or the heating of the precursor, and then the heat treatment of the precursor in a first stage with a total time t 1, wherein in the first stage the precursor is heat-treated at a temperature in a temperature range between T α+γ/γ and T 1, and then the cooling of the precursor to a temperature T 2, and then the heat treatment of the precursor in a second stage at the temperature T 2 for a time t 2, and then the cooling of the precursor to room temperature, wherein the heat treatment is at least intermittently performed in a hydrogenous atmosphere while the exposed parts of the surface of the precursor are in direct contact with the hydrogenous atmosphere, wherein the temperature T 1 > T 2, T 1 is above T α+γ/γ and T 2 is below T α/α+γ. the provision of a precursor having a composition substantially consisting of 2 % w/w ≤ Co ≤ 30 % w/w 0.3 % w/w ≤ V ≤ 5.0 % w/w 0 % w/w ≤ Cr ≤ 3.0 % w/w 0 % w/w ≤ Si ≤ 5.0 % w/w 0 % w/w ≤ Mn ≤ 5.0 % w/w 0 % w/w ≤ Al ≤ 3.0 % w/w 0 % w/w ≤ Ta ≤ 0.5 % w/w 0 % w/w ≤ Ni ≤ 1.0 % w/w 0 % w/w ≤ Mo ≤ 0.5 % w/w 0% w/w ≤ Cu ≤ 0.2 % w/w 0 % w/w ≤ Nb ≤ 0.25 % w/w 0 % w/w ≤ Ti ≤ 0.05 % w/w 0 % w/w ≤ Ce ≤ 0.05 % w/w 0 % w/w ≤ Ca ≤ 0.05 % w/w 0 % w/w ≤ Mg ≤ 0.05 % w/w 0 % w/w ≤ C ≤ 0.02 % w/w 0 % w/w ≤ Zr ≤ 0.1 % w/w 0 % w/w ≤ O ≤ 0.025 % w/w 0 % w/w ≤ S ≤ 0.015 % w/w rest iron and up to 0.2 % w/w melting-related impurities, wherein the precursor has a phase transition from a BCC phase area into a BCC/FCC mixed area to an FCC phase area, wherein at increasing temperature the phase transition between the BCC phase area and the BCC/FCC mixed area occurs at a first transition temperature T α/α+γ and at further increasing temperature the transition between the BCC/FCC mixed area and the FCC phase area occurs at a second transition temperature T α+γ/γ and the difference T α+γ/γ - T α/α+γ is less than 45 K, preferably less than 25 K, the partial coating of the precursor with a ceramic-forming layer, wherein the precursor has the form of a sheet with a first surface and a second, opposite surface, wherein at least between 20% and 80%, preferably between 30% and 70%, particularly preferred between 50% and 70% of the first surface and between 20% and 80%, preferably between 30% and 70%, particularly preferred between 50% and 70% of the second surface remain free of the ceramic-forming layer, the heat treatment of the partially coated precursor, wherein the heat treatment comprises the heating of the precursor, and then the heat treatment of the precursor in a first stage with a total time t 1, wherein in the first stage the precursor is heat-treated at a temperature in a temperature range between T α+γ/γ and T 1, and then the cooling of the precursor to room temperature, or the heating of the precursor, and then the heat treatment of the precursor in a first stage with a total time t 1, wherein in the first stage the precursor is heat-treated at a temperature in a temperature range between T α+γ/γ and T 1, and then the cooling of the precursor to a temperature T 2, and then the heat treatment of the precursor in a second stage at the temperature T 2 for a time t 2, and then the cooling of the precursor to room temperature, wherein the heat treatment is at least intermittently performed in a hydrogenous atmosphere while the exposed parts of the surface of the precursor are in direct contact with the hydrogenous atmosphere, wherein the temperature T 1 > T 2, T 1 is above T α+γ/γ and T 2 is below T α/α+γ.