A method for coating a substrate, which has a width and a length, with an alloy comprising at least a first and a second material as alloy components and having a variable alloy ratio by means of magnetron cathode sputtering, comprising (a) a magnetron sputtering cathode with a target comprising the alloy components and a magnet arrangement which is arranged behind the target when viewed from the substrate for forming at least one erosion section on the surface of the target, wherein (b) the surface of the target comprises at least a first section of the first material and a second section of the second material, (c) the first section and the second section adjoin each other and form a common boundary line on the surface of the target, and (d) the erosion section is positioned in the area of the boundary line so that a first part of the erosion section lies on the first target section and a second part of the erosion section lies on the second target section, characterized by (e) changing the alloy ratio by moving the erosion section transversely with respect to the boundary line, and/or adjusting an acute angle α between the boundary line and the longitudinal direction of the erosion section in a plane parallel to the surface of the target, and/or adjusting an angle β between the surface of the magnet arrangement and the surface of the target facing the substrate, and (f) changing the relative position between the magnetron sputtering cathode and the surface of the substrate by linearly moving the substrate parallel with respect to the surface of the substrate. (a) a magnetron sputtering cathode with a target comprising the alloy components and a magnet arrangement which is arranged behind the target when viewed from the substrate for forming at least one erosion section on the surface of the target, wherein a target comprising the alloy components and a magnet arrangement which is arranged behind the target when viewed from the substrate for forming at least one erosion section on the surface of the target, (b) the surface of the target comprises at least a first section of the first material and a second section of the second material, (c) the first section and the second section adjoin each other and form a common boundary line on the surface of the target, and (d) the erosion section is positioned in the area of the boundary line so that a first part of the erosion section lies on the first target section and a second part of the erosion section lies on the second target section, characterized by (e) changing the alloy ratio by moving the erosion section transversely with respect to the boundary line, and/or adjusting an acute angle α between the boundary line and the longitudinal direction of the erosion section in a plane parallel to the surface of the target, and/or adjusting an angle β between the surface of the magnet arrangement and the surface of the target facing the substrate, and moving the erosion section transversely with respect to the boundary line, and/or adjusting an acute angle α between the boundary line and the longitudinal direction of the erosion section in a plane parallel to the surface of the target, and/or adjusting an angle β between the surface of the magnet arrangement and the surface of the target facing the substrate, and (f) changing the relative position between the magnetron sputtering cathode and the surface of the substrate by linearly moving the substrate parallel with respect to the surface of the substrate.