Masato Sagawa, the Japanese inventor of a critical new magnet technology in the 1980s, is hoping to change the world again by producing the “ultimate” magnet. The magnet would eliminate — or significantly reduce — the use of the heavy rare earth element dysprosium, which resists extremely high temperatures that would otherwise erode magnets' strength in jet engines, electric vehicle motors, and other industrial and high-tech applications.  Dysprosium in solid metallic form. Dy