Abstract: The film is composed of an alternate lamination of unit iron layers and unit layers of ferromagnetic iron compound such as Fe.sub.3 Al, Fe.sub.3 Si, Fe.sub.3 Ge and Fe.sub.3 Ga. The thickness of the both unit layers is less than 70 .ANG.. The film has a high saturation magnetization more than 230 emu/g and a high thermal stability so that the film is particularly applicable to a magnetic head core.

Abstract: An electric power supply in pulse form is applied between a welding electrode and workpieces. The temperature of a molten pool is measured by a radiation-type thermometer when no power supply pulse is applied, and the welding condition is controlled in response to an output signal of the radiation-type thermometer.

Abstract: In a welding apparatus having a plurality of electrodes and adapted for carrying out welding operation on a workpiece by alternately supplying currents to the individual electrodes through switching elements, an apparatus and method of controlling the currents supplied to the electrodes, comprising selecting the values of the currents supplied to the individual electrodes depending on the material of the workpiece, and carrying out the welding operation on the workpiece by alternately supplying the currents of the selected values to the individual electrodes respectively through the switching elements. The method is featured by the fact that the ratio between the individual currents is selected under the condition that the sum of the values of all the currents is maintained at a predetermined value.