PLD-fabricated (Nd or Pr)–Fe–B Thick-film Magnets Applied to Small Stepping Motors

We have fabricated isotropic Pr–Fe–B thick-film magnets (thickness: 0.25 mm) on a stainless shaft using a pulsed laser deposition method. Subsequently, we applied these magnets to a small stepping motor (diameter: < 3 mm) by taking advantage of the Pr2Fe14B phase with a large anisotropic magnetic field at approximately 300 K. We focused on the fact that, compared with the linear expansion coefficient of Pr element (6.7 × 10
^-6
1/K ), the expansion coefficient of Nd element (9.6 × 10
^-6
1/K ) is closer to that of stainless steel (10 – 11×10
^-6
1/K). Moreover, we compared the temperature dependence of magnetic properties and the mechanical characteristic of Nd–Fe– B and Pr–Fe–B thick-film magnets on a stainless substrate (shaft).