10.3 Read Head in Magnetic Data Storage
229
10.3.2 Role of GMR in Magnetic Data Storage
The largest technological application of GMR has been realized in the data storage
industry. Based on GMR technology, IBM was the pioneer to produce the market
hard disks. In recent time, the working of most of the disk drives is exploiting this
technology. There is an aspiring demand and hence, a steady rise of requirement
for magnetic data storage stimulated from various applications, such as novel and
new generation of PC operating systems, increasing applications of internet systems,
advent of diversified modern days consumer electronics. This leads to the development of ‘Hard disk based magnetic data storage device’. Such development in turn
motivates the scientific and industrial community to look for new solutions, suitable
media, heads, tribology and system electronics.
10.3.3 Internal Structure of a Magnetic Hard Disk
The hard disk drive is basically the integration of many key technologies and the associated components, which include storage medium, read/write transducer, channel
coding/decoding, servo control, head/disk interface, tribology, electromechanical
and electromagnetic systems. Let us discuss the physics and material aspects of the
storage medium and read/write heads, related to the magnetic recording (Fig. 10.3).
Hard disk drive consists of thin-film structures, which is composed of multiple
layers of thin films. Such structure is fabricated on NiP-coated aluminium alloy,
glass substrate, etc. In earlier days, a single magnetic layer is only employed as
the recording layer in the hard disk media. Polycrystalline alloy of Co, Cr and Pt
was normally used for that purpose, along with additional elements like Ta or B in
order to improve the magnetic properties. In recent time, magnetic hard disk media
involves multiple magnetic layers as the recording layer. In an attempt to improve
Fig. 10.3 Schematic diagram of read and write head sensor for magnetic storage devices and media
(Adapted and redrawn from IGCSE ICT—Magnetic Storage Devices and Media https://www.
ictlounge.com/html/magnetic_storage_media.htm)
229
10.3.2 Role of GMR in Magnetic Data Storage
The largest technological application of GMR has been realized in the data storage
industry. Based on GMR technology, IBM was the pioneer to produce the market
hard disks. In recent time, the working of most of the disk drives is exploiting this
technology. There is an aspiring demand and hence, a steady rise of requirement
for magnetic data storage stimulated from various applications, such as novel and
new generation of PC operating systems, increasing applications of internet systems,
advent of diversified modern days consumer electronics. This leads to the development of ‘Hard disk based magnetic data storage device’. Such development in turn
motivates the scientific and industrial community to look for new solutions, suitable
media, heads, tribology and system electronics.
10.3.3 Internal Structure of a Magnetic Hard Disk
The hard disk drive is basically the integration of many key technologies and the associated components, which include storage medium, read/write transducer, channel
coding/decoding, servo control, head/disk interface, tribology, electromechanical
and electromagnetic systems. Let us discuss the physics and material aspects of the
storage medium and read/write heads, related to the magnetic recording (Fig. 10.3).
Hard disk drive consists of thin-film structures, which is composed of multiple
layers of thin films. Such structure is fabricated on NiP-coated aluminium alloy,
glass substrate, etc. In earlier days, a single magnetic layer is only employed as
the recording layer in the hard disk media. Polycrystalline alloy of Co, Cr and Pt
was normally used for that purpose, along with additional elements like Ta or B in
order to improve the magnetic properties. In recent time, magnetic hard disk media
involves multiple magnetic layers as the recording layer. In an attempt to improve
Fig. 10.3 Schematic diagram of read and write head sensor for magnetic storage devices and media
(Adapted and redrawn from IGCSE ICT—Magnetic Storage Devices and Media https://www.
ictlounge.com/html/magnetic_storage_media.htm)