Title :
Thermal agitation of magnetization in CoCrPt perpendicular recording media
Author :
Shimatsu, T. ; Uwazumi, H. ; Sakai, Y. ; Otsuki, A. ; Watanabe, I. ; Muraoka, H. ; Nakamura, Y.
Author_Institution :
Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan
fDate :
7/1/2001 12:00:00 AM
Abstract :
Magnetic and structural properties of CoCrPt based perpendicular recording media required to achieve both high thermal stability and low-noise performance are discussed, based on experimental results obtained using a pulse magnetometer. Experimental and theoretical analysis reveal that for CoCrPt based media of 20 nm thickness having the thermal stability factor KuV/(kT)≈80, the maximum achievable value of the ratio of remanence coercivity to anisotropy field of grains, Hr/Hk, is ~0.35. Furthermore, if the strictest condition of demagnetizing factor, 4π, for perpendicular media is assumed, in order to realize a large squareness M r/Ms of nearly 1.0, which is required to resist the thermal agitation effect, we find that the value of perpendicular magnetocrystalline anisotropy, Ku, has to be more than 3 times larger than 2πMs2
Keywords :
chromium alloys; cobalt alloys; coercive force; magnetic recording noise; magnetic thin films; perpendicular magnetic anisotropy; perpendicular magnetic recording; platinum alloys; remanence; thermal stability; 20 nm; CoCrPt; anisotropy field; demagnetizing factor; experimental results; low-noise performance; magnetic properties; magnetization; perpendicular magnetocrystalline anisotropy; perpendicular recording media; remanence coercivity; structural properties; theoretical analysis; thermal agitation effect; thermal stability; Anisotropic magnetoresistance; Magnetic analysis; Magnetic anisotropy; Magnetic properties; Magnetization; Magnetometers; Perpendicular magnetic anisotropy; Perpendicular magnetic recording; Thermal factors; Thermal stability;
Journal_Title :
Magnetics, IEEE Transactions on
