High density digital magnetic and magneto-optical storage devices are widely used in audio, video, and data processing information technology, as well as in CAD/CAM computer systems. These widespread uses generate a continually increasing demand for both increased information storage densities and capacities, and for reduced access times. Hence, the materials engineering of high density storage media, with a high signal to noise ratio, and the associated design of sophisticated read and write heads, form the basis of major technological research. This research is especially complex because, ideally, the recorded information should be both erasable and, at the same time, secure and accessible over periods of many decades. As a result, research on these complex problems requires a multidisciplinary approach which utilizes the expertise in such widely differing fields as organic, inorganic, and solid state chemistry, metallurgy, solid state physics, electrical and mechanical engineering, and systems analysis. Often, further research specialization is necessary in each of these different disciplines. For instance, solid state physics and chemistry address the problems of crystallographic structure and phase diagram determination, magnetism, and optics, but more advanced research methods, such as high resolution electron microscopy and electronic band structure calculations, are necessary to understand the microstructure of particulate recording media or the electronic spectra of magneto-optical recording media.

This book treats the various aspects of noise from magnetic recording media and the impact on system performance. Several authors present discussions of: materials and processes used to fabricate media for computer data storage, theoretical aspects of noise and micromagnetic behavior, experimental methods and characterization, and system analysis. In the past decade thin film recording media have largely displaced particlate media in rigid disk recording systems. During the same period of time the field has evolved from the prevalent belief that thin film media were virtually noiseless to a detailed understanding of the origin and the manifestation of noise in these new media. This understanding has lead to the ability to make the very low noise media needed in present applications. The present state of understanding of both particulate and thin film media is summarized.

This book treats the various aspects of noise from magnetic recording media and the impact on system performance. Several authors present discussions of: materials and processes used to fabricate media for computer data storage, theoretical aspects of noise and micromagnetic behavior, experimental methods and characterization, and system analysis. In the past decade thin film recording media have largely displaced particlate media in rigid disk recording systems. During the same period of time the field has evolved from the prevalent belief that thin film media were virtually noiseless to a detailed understanding of the origin and the manifestation of noise in these new media. This understanding has lead to the ability to make the very low noise media needed in present applications. The present state of understanding of both particulate and thin film media is summarized.

In addition to grain size and distribution, compositional segregation of non-magnetic materials was also studied. A series of CoCrPtTa, CoCrPtB 5, and CoCrPtB8 thin film longitudinal media were prepared under ostensibly identical sputtering conditions. High resolution TEM revealed that adding 5% or 8% boron to the magnetic layer resulted in significantly reduced average grain size compared to the media with a CoCrPtTa magnetic layer. It was also found that by adding boron, SNR and media noise properties were improved. While not affecting the lattice mismatch between the underlayer and the magnetic layer, the presence of B was found to enhance Cr segregation to cores as well as grain boundaries.