TY - JOUR
T1 - Formation of Magnetic Cluster and Remanence Coercivity in Granular-Type Perpendicular Media
AU - Shimatsu, T.
AU - Oikawa, T.
AU - Inaba, Y.
AU - Muraoka, H.
AU - Nakamura, Y.
N1 - Funding Information:
Manuscript received January 2, 2003. This work was supported in part by the IT-program (RR2002) of MEXT, in part by Research for the Future Program of JSPS (JSPS-RFTF 99R14401), and in part by SRC. T. Shimatsu, Y. Inaba, H. Muraoka, and Y. Nakamura are with Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan (e-mail: shimatsu@riec.tohoku.ac.jp). T. Oikawa is with Fuji Electric Co., Ltd., Matsumoto 390-0821, Japan (e-mail: oikawa@kiroku.riec.tohoku.ac.jp). Digital Object Identifier 10.1109/TMAG.2003.816289
PY - 2003/9
Y1 - 2003/9
N2 - The magnetic cluster size Dcluster of perpendicular recording media, which is a main factor in media noise, is discussed in terms of demagnetizing field of magnetic clusters, remanence coercivity, and magnetization switching. It was shown that the values of remanence coercivity obtained by subtracting thermal agitation effect H0 are ∼70% of those calculated using the Stoner-Wohlfarth model taking account of the c-axis distribution, HrS-W even in CoPtCr-SiO2 media with well segregated grains. Demagnetizing field of magnetic cluster H d is calculated as a function of the ratio of Dcluster to film thickness, δ. An intrinsic remanence coercivity H0 int was obtained by compensating the H0 value by the Hd(H0int = H0 + Hd). The H0int values are very close to those of Hr S-W especially in media with well-segregated grains. This result means that the magnetization reversal of these media is mainly determined by coherent rotation of magnetization; however, the demagnetizing field of magnetic cluster, besides thermal agitation effect, reduces the value of H 0.
AB - The magnetic cluster size Dcluster of perpendicular recording media, which is a main factor in media noise, is discussed in terms of demagnetizing field of magnetic clusters, remanence coercivity, and magnetization switching. It was shown that the values of remanence coercivity obtained by subtracting thermal agitation effect H0 are ∼70% of those calculated using the Stoner-Wohlfarth model taking account of the c-axis distribution, HrS-W even in CoPtCr-SiO2 media with well segregated grains. Demagnetizing field of magnetic cluster H d is calculated as a function of the ratio of Dcluster to film thickness, δ. An intrinsic remanence coercivity H0 int was obtained by compensating the H0 value by the Hd(H0int = H0 + Hd). The H0int values are very close to those of Hr S-W especially in media with well-segregated grains. This result means that the magnetization reversal of these media is mainly determined by coherent rotation of magnetization; however, the demagnetizing field of magnetic cluster, besides thermal agitation effect, reduces the value of H 0.
KW - Demagnetizing field
KW - Magnetic cluster size
KW - Magnetization reversal mechanism
KW - Perpendicular recording media
KW - Remanence coercivity
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U2 - 10.1109/TMAG.2003.816289
DO - 10.1109/TMAG.2003.816289
M3 - Article
AN - SCOPUS:0141919451
VL - 39
SP - 2335
EP - 2337
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
SN - 0018-9464
IS - 5 II
ER -