TY - JOUR
T1 - Improvement of magnetic intergranular isolation and evaluation of read/write characteristics on SmCo5 perpendicular magnetic thin films
AU - Asahi, Toru
AU - Koizumi, Isao
AU - Egawa, Yuko
AU - Yoshino, Masahiro
AU - Sugiyama, Atsushi
AU - Hokkyo, Jiro
AU - Kiya, Takanori
AU - Ariake, Jun
AU - Ouchi, Kazuhiro
AU - Osaka, Tetsuya
N1 - Funding Information:
This work was partly supported by the Grant-in-Aid for specially promoted research “Establishment of electrochemical device engineering” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, and by the Global COE program “Center for practical chemical wisdom” from MEXT.
PY - 2010/12
Y1 - 2010/12
N2 - SmCo5 alloy is a promising candidate for ultra-high-density perpendicular magnetic recording (PMR) media because of its high uniaxial magnetocrystalline anisotropy Ku of more than 1.1×10 8 erg/cm3. Previously, we successfully achieved high Ku in a sputter-deposited SmCo5 thin film by introducing a Cu/Ti dual underlayer. However, in order to apply the SmCo5 films to practical PMR media, it is necessary to decrease medium noise. A granulated magnetic film comprising of small and magnetically decoupled grains is effective in reducing the medium noise. In this paper, we have proposed a new granular film that is fabricated by partial thermodiffusion of Cu between the SmCo continuous layer and the Cu underlayer, which is granulated using compositional segregation caused by the addition of Ta2O5. We have analyzed the magnetic properties, magnetic domain size, and magnetization reversal process of the proposed SmCo5 film. The magnetic domain size decreased and the magnetization reversal process changed from the magnetic-wall-motion mode to a coherent rotation mode to some extent on isolation of magnetic grains. The read/write characteristics of granulated SmCo5 double-layered media were also evaluated. The medium noise decreased and the signal-to-noise ratio increased for the granulated double-layered (PMR) medium.
AB - SmCo5 alloy is a promising candidate for ultra-high-density perpendicular magnetic recording (PMR) media because of its high uniaxial magnetocrystalline anisotropy Ku of more than 1.1×10 8 erg/cm3. Previously, we successfully achieved high Ku in a sputter-deposited SmCo5 thin film by introducing a Cu/Ti dual underlayer. However, in order to apply the SmCo5 films to practical PMR media, it is necessary to decrease medium noise. A granulated magnetic film comprising of small and magnetically decoupled grains is effective in reducing the medium noise. In this paper, we have proposed a new granular film that is fabricated by partial thermodiffusion of Cu between the SmCo continuous layer and the Cu underlayer, which is granulated using compositional segregation caused by the addition of Ta2O5. We have analyzed the magnetic properties, magnetic domain size, and magnetization reversal process of the proposed SmCo5 film. The magnetic domain size decreased and the magnetization reversal process changed from the magnetic-wall-motion mode to a coherent rotation mode to some extent on isolation of magnetic grains. The read/write characteristics of granulated SmCo5 double-layered media were also evaluated. The medium noise decreased and the signal-to-noise ratio increased for the granulated double-layered (PMR) medium.
KW - High Ku material
KW - Perpendicular magnetic recording
KW - Read/Write (R/W) characteristics
KW - SmCo thin film
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U2 - 10.1016/j.jmmm.2010.07.045
DO - 10.1016/j.jmmm.2010.07.045
M3 - Article
AN - SCOPUS:77956190332
VL - 322
SP - 3784
EP - 3788
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
SN - 0304-8853
IS - 23
ER -