| 摘要 |
PURPOSE:To reduce high-magnetic resonance absorptive half-value width DELTAH by adding 3.0wt% of CaO to a magnetic material a garnet type crystal structure but does not contain Ca ion. CONSTITUTION:0-3.0wt% of CaCO3 is added, as CaO, to a magnetic material having a garnet type multi-crystal structure without Ca ion content, e.g. a material having a chemical composition of Y3Fe5-yAl5yO12. And then, thus prepared material is mixed by using such an apparatus as a steel-built ball mill, and after temporarily calcined at 900 deg.C-1200 deg.C, the material is again pulverized by the ball mill, compression-formed and again calcined in an atmosphere at a temperature ranging from 1200 deg.C-1500 deg.C for 1-20hrs. It is possible, by doing so, to obtain a high-density calcined body without changing values of saturation magnetization 4piMs and curie temperature Tc, and it is also possible to reduce value of DELTAH. Further, the reason why the upper limit of CaO was set to 3.0wt% is because if more than 3.0wt% of CaO was added, vacant pores are increased and, therefore, value of DELTAH becomes large. |
