Review of Fabrication and Characterization of Nd–Fe–B Thick Films for Magnetic Micromachines

Abstract

Isotropic Nd-Fe-B thick film magnets were prepared by a high-speed pulsed laser deposition method followed by a post annealing. The deposition rate of 90 m/h could be successfully achieved, and a pulse annealing was adopted as the post annealing process in order to enhance coercivity. Use of a substrate heating system under the high deposition rate enabled us to obtain anisotropic thick films with ( ) max of approximately 120 kJ/m 3 , which show the potential for an improvement in the properties of the micromachines. Novel micromachines comprising the isotropic films were introduced.

Effect of laser beam parameters on magnetic properties of Nd–Fe–B thick-film magnets fabricated by pulsed laser deposition

“…The maximum obtained DR is 11.8 lm/(hÁW), which is 30% larger than the highest previously reported deposition rate by PLD. 6 As Fig. 2 shows, the film magnets obtained for DF rate > 0.2 have reproducible magnetic properties.…”

“…A typical microstructure of the annealed films has been reported elsewhere. 6 The scattering in H c , I r , and the Nd content is low for films deposited under DF rate > 0.2, which suggests that reproducible magnetic properties can be expected under these conditions. When the laser beam is focused on the target, it forms a deep groove, and the direction in which particles are emitted from the target varies erratically.…”

“…We fabricated a film by PLD with a high deposition rate of 9 lm/(hÁW); this film had a coercivity of about 1000 kA/m, a remanence of about 0.6 T, and a (BH) max value of 60 kJ/m 3 (Ref. 6).…”

“…We found that controlling the laser energy density enabled us to obtain stable magnetic properties and deposition rates that exceed previously reported rates. 6 …”

Nd–Fe–B thick film magnets with Nb additive prepared by vacuum arc deposition method

“…11 We have already reported on the isotropic Nd-Fe-B thick film magnets prepared by using a PLD (pulsed laser deposition) method and applied them to several micro machines. 12 The characteristic of the method was the high deposition rate up to 90 lm/h on a 5 Â 5 mm 2 substrate by taking advantage of small particles (droplets) emitted from an Nd-Fe-B target. Recently, we also reported on the vacuum arc deposition (VAD)-fabricated isotropic Nd-Fe-B thick film magnets.…”