Levitation force of a stack of epitaxial YBa2Cu3O7-delta films

The levitation force of three epitaxial YBa2Cu3O7-delta films and a stack made of these films was measured. The films show a very high force density of about 100 N cm(-3) and a large hysteresis of the force versus distance relation. The filmstack provides a levitation force which is nearly as high as the sum of the forces of the single films. The magnetic stiffness of the stack is comparable to that of melt-textured bulk samples and shows a crossover from a B-1.5 to a B-2 dependence as observed on single films and melt-textured samples. The use of filmstacks for levitation devices may offer several specific advantages.