| 摘要 |
<p>A data store comprises a card (1) carrying superimposed permanently structured layers having selected spaced regions (8, 10) which contain anisotropic magnetic particles aligned along different respective first axes (4, 5) in respective layers. The remaining regions of the layers contain anisotropic magnetic particles having either no overall orientation, or being aligned along respective further axes (6, 7) which are not parallel to any of the first axes. Different sensors read data from different layers, thereby increasing the data storage capacity of the card.</p> |
