Magnetic reading head

The GMR multilayers require a large saturation field (>10000 Oe) to overcome the antiferromagnetic coupling of magnetic layers in order to display the large GMR ratios. These multilayers are potentially useful for application in magnetic read heads. 

Figure 10.134 Schematic representation of a cell for microextraction of magnetic reading heads.

Table 10.19 Minimum detection limits for anionic contaminants on a single magnetic reading head after microextraction coupled to microbore ion chromatography.

Magnetic random-access memory (MRAM) is a new type of computer memory. MRAMs retain their state of magnetization even with the power off, but unlike present forms of nonvolatile memory, they have switching and rewritability rates that challenge (are faster than) those of conventional RAM. In today s read heads as well as those of MRAMs, key features are made of ferromagnetic metallic alloys. Such metal-based devices make up the first—and most mature—of the various categories of spintronics. 

FIGURE 9.13 Two ferromagnetic layers, as in a magnetic hard disk read head, illustrating pinning hy an antiferromagnetic layer. 

The electronic and magnetic properties of nanolayers are important in devices formed from electronic materials that are more conventional. We have already discussed quantum well lasers (see Chapter 8) and giant magnetoresistance (GMR) devices used for hard disk read heads (see Chapter 9). Quantum well lasers may be an important component of light-based computers. Other possibilities include magnets with unusual properties (Section 11.2). 

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