Application of PLD-Fabricated Thick-Film Permanent Magnets

Isotropic Nd-Fe-B thick-film magnets have been prepared using a pulsed laser deposition (PLD) method with the control of laser energy density (LED) followed by post-annealing. The characteristics of the method are a high deposition rate up to several tens of microns per hour together with a reliability of magnetic properties due to the good transfer of composition from an Nd-Fe-B target to a film. Several micro-machines comprising the isotropic Nd-Fe-B films such as a miniaturized DC motor and a swimming machine in liquid were demonstrated. Furthermore, the deposition of isotropic Nd (or Pr)-Fe-B thick-film magnets on a Si or glass substrate was carried out to apply the films to various micro-electro-mechanical-systems (MEMS). We also introduced the preparation of isotropic Sm-Co, Fe-Pt, and nano-composite Nd-Fe-B+α-Fe film magnets synthesized using the PLD

Shooting the lecture scene using computer-controlled cameras based on situation understanding and evaluation of video images

In this paper, we propose a computer-controlled camera work that shoots object scenes to model the professional cameramen’s work and selects the best image among plu-ral video images as a switcher. We apply this system to a shooting of a lecture scene. In the first, our system es-timates a teacher’s action based on features of a teacher and a blackboard. In the next, each camera is directed to a shooting area based on the teacher’s action, automatically. In the last, this system selects the best image among plural images under the evaluation rule. Moreover, we have tried experiments of shooting lecture scene and have confirmed the effectiveness of our approach. 1

Ferroelectric Instability and Dimensionality in Bi-Layered Perovskites and Thin Films

The dielectric and thermal properties of Bi (bismuth)-layered perovskite SrBi2Ta2O9 (SBT) are discussed in comparison with ferroelectric thin BaTiO3 films. Although these two perovskites exhibit quite a different nature, the dielectric properties of BaTiO3 thin film are similar to those in bulk SBT. The dielectric properties and pseudo-two-dimensional structure between SBT and thin film suggest that the bulk layered ferroelectric SBT is a good model of ultra-thin ferroelectric film with two perovskite layers, free from any misfit lattice strain with substrate and surface charge at the interface with electrodes. Based on the mechanism of ferroelectric phase transition of SBT, it seems plausible that the ferroelectric interaction is still prominent but shows a crossover from ferroelectric to antiferroelectric interaction in perovskite ultra-thin films along the tetragonal axis

Computer Simulation of Enhancement of Coerciviy in Nd-Fe-B/(Nd,Dy)-Fe-B Composite Magnets

The coercivity Hc of Nd2Fe14B magnets and Nd2Fe14B/(Nd0.7Dy0.3)2Fe14B composite magnets were calculated by computer simulation based on the micromagnetic theory under assumptions that Nd2Fe14B and (Nd0.7Dy0.3)2Fe14B grains have magnetically deteriorated layers on their surfaces and diffusion of Dy from (Nd0.7Dy0.3)2Fe14B grains to Nd2Fe14B ones through the contacting boundaries recovers the magnetic anisotropy of the deteriorated layers of Nd2Fe14B grains. Hc of Nd2Fe14B/(Nd0.7Dy0.3)2Fe14B composite magnets increased by the diffusion of Dy from (Nd0.7Dy0.3)2Fe14B grains to Nd2Fe14B ones and the resultant recovery of the anisotropy field of deteriorated layers of Nd2Fe14B grains. The Hc vs fraction of (Nd0.7Dy0.3)2Fe14B grains curve were convex for the magnets with the degree of alignment between 0.94 and 0.99, which suggests that the above composite magnets have larger Hc values than the alloy-magnets with the same Dy content, and that we can save the consumption of Dy by using these composite magnets

Improvement in morphology of multi-layered Nd-Fe-B/Fe_3B thick film magnets prepared by PLD method

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Order/disorder phase composite Fe-Pt exchange-spring film magnets

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Nd-Fe-B thick-film magnets prepared by high laser energy density

An observation of microstructure revealed that a laser-irradiated Nd-Fe-B target under the laser energy density (LED) above 10 J/cm2 enabled us to prepare isotropic nano-composite thick-film magnets with good magnetic properties due to a dispersed α-Fe + Nd-Fe-B structure. The formation of the structure is attributed to the etching process of a target during a deposition. Moreover, the control of composition in the nano-composite film enhanced (BH)max value up to approximately 130 kJ/m3.2015 IEEE International Magnetics Conference, INTERMAG 2015; Beijing; China; 11 May 2015 through 15 May 201

Reduction in Flux Loss of an Nd-Fe-B Bonded Ring Magnet for an SPM Motor

We have previously proposed a simulation method of an initial flux loss in permanent magnets using finite element method, and confirmed that predicted flux loss of an Nd-Fe-B boned ring magnet showed good agreement with measured flux loss. In this paper, we applied our proposed method to an Nd-Fe-B boned ring magnet in an SPM motor. We modeled a rotor composed of an Nd-Fe-B bonded ring magnet and a soft magnetic core made from silicon steels, and carried out the simulations for magnetizing process and prediction process of the flux loss. From the simulation results, we found that the inner side of the ring magnet has large flux loss. In order to reduce in flux loss, we enhanced the coercivity in the inner side of the ring magnet by partial replacement with another bonded magnet with high coercivity. Consequently, we found that the ring magnet with locally enhanced coercivity is effective to reduce in the flux loss