| 摘要 |
A magnetic structure comprises a plurality of layers where layers have a different chemical composition and a different magnetic anisotropy. The layers can be anisotropic in coercivity and/or direction of easy axis. In addition magnetic anisotropy within a layer can exhibit a step change and may exhibit a periodicity. A method of making a magnetic structure comprises forming a layer of powder 4 on a substrate 1, melting powder using electromagnetic energy, solidifying the melted powder while simultaneously applying an external magnetic field thereby forming a solid layer which has magnetic anisotropy and repeating this process to form a layered structure with layers having different magnetic anisotropy. Apparatus for producing a magnetic material with controlled magnetic anisotropy comprises a powder dispenser 4 from which powder can be dispensed onto a substrate 1, a radiation source 5 which can be used to melt powder, means 10 to cool the molten powder and means 21 to apply a magnetic field to the molten powder. |
