Magnetic core, method and device for its production and use of such a magnetic core

A method for the production of a magnetic core with the steps:

• preparing an alloy as a belt-shaped material, whereby the alloy consists of Fe100-a-b-c-d-x-y-zCuaNbbMcTdSixByZz and up to 1 at. % of impurities, wherein M is one or more of the elements Mo, Ta or Zr;
• T is one or more of the elements V, Cr, Co or Ni;
• and Z is one or more of the elements C, P or Ge, and
• 0 at. %≦a<1.5 at. %,
• 0 at. %≦b<4 at. %,
• 0 at. %≦c<4 at. %,
• 0 at. %≦d<5 at. %,
• 12 at. %<x<18 at. %,
• 5 at. %<y<12 at. %, and
• 0 at. %≦z<2 at. %,
• heat treating the belt-shaped material at a heat-treatment temperature of between 450 and 750° C.;
• loading the heat-treated belt-shaped material with a tensile force in the longitudinal direction of the belt-shaped material in order to produce a tensile stress of between 30 MPa and 500 MPa in the belt-shaped material, to produce a soft-magnetic strip material from the belt-shaped material;
• determining of at least one magnetic measurement value of the soft-magnetic strip material being produced, and
• adjusting of the tensile force for setting the tensile stress in reaction to the determined magnetic measurement value;
• and
• winding up at least one defined section of the soft-magnetic strip material being produced to produce the magnetic core.