An MTJ MRAM cell is formed by using a reactive ion etch to pattern an MTJ stack on which there has been formed a bilayer TaTaN hard mask. The ballast circuit comprises an electromagnetic ballast arrangement for driving the lamps and an ignitor circuit for starting the lamps. , bio-oil, on a large scale production. The pattern on the roller is transferred on the separator to have a predetermined groove pattern. The gas jet cooling device can cool the strip rapidly and uniformly even when the distance between the strip and the front face of each windbox is shorter and the size of a cooling chamber is smaller than the conventional ones. The first connecting structure further includes a heat conductor, supported by the substrate, in contact with a first radial heat conductor of the plurality of radial heat conductors.