Comparison of properties between Pr–Fe–B and Nd–Fe–B thick-film magnets applied to MEMS

Abstract

We investigated the possibility of R (Nd or Pr)-Fe-B thick-film magnets applied to MEMS. First, an enhancement in the thickness of the Si oxide layer on a Si substrate enabled us to increase the adhesion force between the Si substrate and Nd-Fe-B film. Then, after depositing a glass buffer layer on the Si substrate to obtain a thicker Si oxide layer, we compared the mechanical characteristics and magnetic properties of both Pr-Fe-B and Nd-Fe-B films. As the thickness of the glass buffer layer increased, the thickness of the Pr-Fe-B film could be enhanced without mechanical destruction. We had difficulty in exceeding the thickness of 100 μm in Nd-Fe-B films. Moreover, the (BH) max value of a 127-μm-thick Pr-Fe-B film was higher by approximately 30 kJ m −3 than that of a 92-μm-thick Nd-Fe-B film. The obtained results suggest that a Pr-Fe-B thick-film magnet is more suitable for MEMS applications.

Formation of Fe–Co/glass multilayer films via pulsed laser deposition

“…Their deposition rate also enhanced as DF rate increased. (Fig.3) This correlation between the results in Figs.2 and 3shows the same tendency as the experimental results for a Nd-Fe-B alloy target in a previous study 30). According to their XRD patterns, all films shown in Fig.2were only composed of Fe-Co phases, such as (110), (200), and (211) crystalline planes.…”

“…1(a). Although we created PLDmade glass films as buffer layers to generate Nd (or Pr) -Fe-B film magnets on Si substrates in previous studies, [29][30][31] the effect of DF rate on glass deposition was not described. Therefore, the current article presents new data related to PLD-made glass.…”

“…We have already reported the effect of DF rate on the surface morphology, composition, and magnetic properties of magnetic films fabricated by pulsed laser deposition. 30) In this study, we first optimized the DF rate. The maximum magnetization (J max ) of the as-deposited samples applied magnetic field of 1400 kA m −1 exceeded 2.2 T. For example, an in-plane JH loop with an average composition of Fe 71 Co 29 at DF rate = 0 had J max = 2.4 T. (inset in Fig.…”