Correlation between modulation noise and uniaxial anisotropy in high coercivity thin film recording media

Author(s):  
D.E. Speliotis
Author(s):  
T. P. Nolan

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.


Author(s):  
G.A. Bertero ◽  
R. Sinclair

Pt/Co multilayers displaying perpendicular (out-of-plane) magnetic anisotropy and 100% perpendicular remanent magnetization are strong candidates as magnetic media for the next generation of magneto-optic recording devices. The magnetic coercivity, Hc, and uniaxial anisotropy energy, Ku, are two important materials parameters, among others, in the quest to achieving higher recording densities with acceptable signal to noise ratios (SNR). The relationship between Ku and Hc in these films is not a simple one since features such as grain boundaries, for example, can have a strong influence on Hc but affect Ku only in a secondary manner. In this regard grain boundary separation provides a way to minimize the grain-to-grain magnetic coupling which is known to result in larger coercivities and improved SNR as has been discussed extensively in the literature for conventional longitudinal recording media.We present here results from the deposition of two Pt/Co/Tb multilayers (A and B) which show significant differences in their coercive fields.


1994 ◽  
Vol 18 (S_1_PMRC_94_1) ◽  
pp. S1_467-470
Author(s):  
Michinobu SUEKANE ◽  
Masao MIYAMURA

1987 ◽  
Vol 23 (5) ◽  
pp. 3645-3647 ◽  
Author(s):  
V. Novotny ◽  
G. Itnyre ◽  
A. Homola ◽  
L. Franco

1997 ◽  
Vol 81 (8) ◽  
pp. 3952-3954 ◽  
Author(s):  
Tao Pan ◽  
Geoffrey W. D. Spratt ◽  
Li Tang ◽  
Li-Lien Lee ◽  
Yongchang Feng ◽  
...  

1995 ◽  
Vol 66 (19) ◽  
pp. 2585-2587 ◽  
Author(s):  
Scott Manalis ◽  
Kenneth Babcock ◽  
James Massie ◽  
Virgil Elings ◽  
Matthew Dugas

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