Anisotropic thick film magnets prepared by high-speed PLD method and their application to an advanced and small motor

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In the study, an improvement in magnetic properties of anisotropic and isotropic Nd-Fe-B film magnets was carried out by using additives. In addition, several applications comprising the films were investigated. The obtained results are as followed.(1) Anisotropic Nd-Fe-B filmsAn obtained film prepared from the Nd_<2.4>Fe_<14>B+Ga_<0.5at.%> target had the coercivity, remanence and (BH)_<max> values of approximately 850 kA/m, 0.95 T and 150 kJ/m^3, respectively. These magnetic properties are superior compared with those for the anisotropic PLD-made Nd-Fe-B films without additives. We also confirmed that the intensities of a X-ray diffraction peaks corresponding to the c-planes such as (004), (006) and (008) of the film were stronger than those of the additive-free film.(2) Isotropic film magnetsPLD-made isotroipic Nd-Fe-B thick film magnets were prepared from targets with Zr, Nb and Ga, respectively. They were crystallized by two annealing methods of conventional annealing (CA) and pulse annealing (PA), respectively. In the case of using Nd_<2.6>Fe_<14>B targets, 0.5 at.% Zr, Nb and Ga addition increased the coercivity of the film by approximately 100～300 kA/m compared with that of additive-free samples prepared by CA method. We also confirmed further increase in coercivity of the film by PA method and the obtained film prepared from a Nd_<2.6>Fe_<14>B+Ga_<0.5at.%> target had large coercivity of approximately 1700 kA/m.(3) ApplicationsWe applied the above-mentioned films to a friction-drive motor and a milli-size motor.