Magnetic and structural properties of CoCrPt based perpendicular recording
media required to achieve both high thermal stability and low-noise perform
ance are discussed, based on experimental results obtained using a pulse ma
gnetometer. Experimental and theoretical analysis reveal that for CoCrPt ba
sed media of 20 nm thickness having the thermal stability factor KuV/(kT)ap
proximate to 80, the maximum achievable value of the ratio of remanence coe
rcivity to anisotropy field of grains, H-r/H-k is similar to0.35. Furthermo
re, in order to realize a large squareness M-r/M-x of nearly 1.0, which is
required to resist the thermal agitation effect at low recording density, w
e find that the value of perpendicular magnetocrystalline anisotropy. K-u n
eeded to be more than three times larger than 2 piM(s)(2). X-ray diffractio
n patterns suggested that the suppression of structural imperfections in th
e HCP structure, particularly in the initial growth layer, is the key issue
to induce larger K-u value in the CoCrPt based media. (C) 2001 Elsevier Sc
ience B.V. All rights reserved.