Study on the characteristics of magnetic levitation for permanent magnets and ferromagnetic materials with various sizes using stacked HTS bulk annuli

► We achieved the stable levitation of irons by magnetized HTS bulk annuli. ► The relationship between magnetized field and sample size was cleared. ► The iron samples smaller than 1 mm diameter could not levitate stably. ► The spherical solenoid magnet was fabricated to levitate small iron samples.