[Co/Ru] 20 Antiferromagnetic Exchange Coupling Energy in [Co/Ru] 20 19
1...1 1.1...1 1.2...1 1.2.1...1 1.2.2...2 1.3...2 1.4...3 1.4.1...3 1.4.2...5 1.5...5 1.5.1...5 1.5.2 SF...6 1.5.3 TAMR...6 2...8 2.1...8 2.2...8 2.3 Co...10 2.4...11 2.5...13
3...14 3.1...14 3.2...14 3.2.1...14 3.2.2...15 3.3...16 3.3.1...16 3.3.2...16 3.3.4...16 3.4...16...17 4.1...17 4.2...17 4.3 M-H...19 4.4 A...20 4.5...22 4.6 Ru...23 4.7... 4.8...24 4.9...25
5...26...27...28
1 1.1 CD DVD MD (HDD) 1.2 1.2.1,1, 1
1.2.2 (MR;Magneto Resistance) GMR(Giant Magneto Resistance) GMR GMR 1.3 - (FC;Ferromagnetic Exchange Coupling) (AFC;Antiferromagnetic Exchange Coupling) 1-3 FC AFC FC AFC Ru (Spacer ) Co Spacer Ru FC AFC (Ru) 1-3 FC AFC
1.4 1.4.1 M-H 1-4 M s t J(>0) 1-4 M-H H E M s H E=-M s thcos -M s thcos +Jcos2 (1) (1) 0 E E θ = 2M sth sin θ 2J sin 2θ = 0 M s thsin -Jsin2 =0 M s thsin -2Jsin cos =0 sin (M s th-2jcos )=0 sin =0 (2-1) M s th-2jcos =0 (2-2) 3
(2-1) =0 = (3-1) (2-2) cos θ = M s t 2J H (3-2) cosθ 1 M s t 2J H 1 1 M s t 2J H 1 2J M s t H 2J M s t (4) (3-2) H=2J/M s t (3-2) cos =1, =0 2J M s t H (5) (3-1) =0 H=-2J/M s t (3-2) cos =-1, = H 2J M s t (6) (3-1) = (3-2) 2M s t cosθ = 2M s t M s t 2J H (7) 2M s tcos Mt-H Mt Mt H H s = ± 2J M s t (8) 2M s t Mt H s J = M s th s 2 J m J = mm th s s 2(2m - 1)
1.4.2 M-H 1-5 J(>0) M s,t 2M s th H AFC J=M s th 1-5 M-H 1.5 1.5.1 HDD V K u V/k B T K u k B T K u V/k B T K u H c =2K u /M s M s HD SFMedia TAMR 5
1) 1.5.2 SF SF (Synthetic Ferri) SF SF nm Ru K u V/k B T SF Co-Cr-Pt-B Ru E-layers Co 2) SFMedia 3)4) 1.5.3 TAMR (TAMR;Thermally Assisted Magnetic Recording) K u V/k B T K u V K u H c H c H c TAMR V K u V/k B T K u H c 6
t 1 t 2 K u V/k B T (a) T c K u K u V/k B T (b) K u
2 2.1 (Ferromagnetic Exchange Coupling;FC) (Antiferromagnetic Exchange Coupling;AFC)., J, AFC. 5)6) 2.2 Cr,Ru,Cu (TM;Transition Metal) (Spacer-layer) Co 3d,4d,5d Co Ru (Ru ) (FC) (AFC) 2-1 [(20 )Co/(t Ru )Ru] 20 t Ru Ru AFC 2-1 [(20 )Co/(t Ru )Ru] 20 t Ru (a) (b) 5) 8
Spacer-layer Ru V,Mo,Rh Spacer-layer 2-2 Spacer-layer AFC 6) 2-2 [(20 )Co/(t TM )TM] 20 t TM 2-1 J 1 t peak Spacer-layer t 1st Spacer-layer P AFC 2-1 1st Spacer-layer Ru t peak =3 J=5erg/cm 2 2-1 Spacer-layer J,t peak, t P 6) 9
Tb-Fe-Co,Gd-Fe-Co Spacer-layer Ru,Rh Spacer-layer ( ) 2-3 7) 1 Spacer-layer 2-3 2-1 Ru,Rh 3,7.9 t peak Spacer-layer 7) 2-3 2M s th w Ru,Rh 8) 2.3 Co 2-4 Co Co 4 M s Co 50 50 2-4 Co Co H s H s Co Co 60 4 M s Co 4 M s -H s =H k E a =K u =(M s H k )/2 K u 8) 2-4 Co 4 M s H s
9) 2.4 M-H J=mM s th s /2(2m-1) M-H Co M s A M s =886emu/cm 3,A=0.39 10-6 erg/cm (a) M-H (b) M-H ( ) Co Co (M-H ) 11
2-6 Co 80% 2-6(a) Co 2-6(b),(c) A Co Co A Co 2-6 Co
2.5 [Co/Ru] 20 ( )Co (2) [Co/TM] 20 Co [Co/Ru] 20
3 3.1 3.2 3.2.1 3-1 3 ( SBH-2306RDE) 3 RF13.56MHz 1kW ( 800V 4A) 2 3 3-1
3.2.2 (76mm 26mm 0.8 1.0mm) 10 ( ) 10 10 40Pa 1.0 10-4 Pa Ar Co,Ru Ru RF Co DC 3-2 Ru Co AFC Ru Co AFC Ru Co 20 3-1 Ar 0.9Pa 20rpm 3-2 3-1 15
3.3 3.3.1 1cm 1cm ( ( )VSM-5 ) VSM, 3.3.2 µm 1/10 3.3.4 ( BH-800TC4) 3 5 M-H 240 3.4 (z ) Co1 (x,y ) z TM Co 2m=20 1 10-6 erg/cm 3-3
4.1 [Co/Ru] 20 Co 4.2 Co 22.5,54.8 M-H 4-1,4-2 AFC Ru 3 4-1 Co 22.5 H s =1.56erg/cm 2 =1.60erg/cm 2 4-2 Co 54.8 H s H s =1.77erg/cm 2 =1.50erg/cm 2 A 1.0 10-6 erg/cm 4-1 t Co =22.5 M-H 17
4-2 t Co =54.8 M-H 4-1 [Co/Ru] 20 Ru Co Co Co Co Co H s Co 4-1 4-2 4.3 18
4.3 M-H 4-3 M-H Co M-H Co M-H A 4-3 M-H Co Ru Co 4-2 4-2 4-4 Co 100 40 M-H H s Ru M-H M-H 19
J M-H, AFC 4-4 M-H (t Co =55 ) 4.4 A M-H A A M-H 4-5 Co 54.8 Co 4-5 A M-H (t Co =55 ) A Co M s 20
A Co A Co X 4-6 4-6 Co X 4-6 44.5deg hcp A 1.0 10-6 erg/cm Co A 1.0 10-6 erg/cm 0.3 10-6 erg/cm A 4-7 4-4 A 0.4 10-6 erg/cm 4-7 A M-H (Etching, t Co =57 ) 21
M-H A M-H A A 0.3 10-6 erg/cm M-H A 1.0 10-6 erg/cm M-H M-H A A 0.4 10-6 erg/cm A M-H A 1.0 10-6 erg/cm 4.5 4-8 M-H Ru 4-8 M-H H s M s M-H H s,m s 1.50erg/cm 2 2.69erg/cm 2 22
4.6 Ru 2.2 Co Ru t Ru [(60 )Co/(t Ru )Ru] 20 t Ru 4-9 Co 100 40 Co 60 Co 60 Ru 3 [6] Ru 3 AFC Ru 5~7 AFC t Ru ( t Co = 60 ) 4.7 Co Co60 Ru Co20 AFM 4-10 20 1 20 1 23
M-H (a) (b) (c) (d) 4-10 (a) 1 (b) 1 (c) 20 (d) 20 10) 4.8 4-11 [Co/Ru] 20 Gd-Fe-Co/Ru/Gd-Fe- Co 4-11 Gd-Fe-Co/Ru/Gd-Fe-Co [Co/Ru] 20 100 Gd-Fe-Co Co 24
10) 4-11 4.9 Co/Ru Co Co Co Co Co M-H Co M-H A M-H Ru Co M-H Co Co/Ru 100 Gd-Fe-Co/Ru/Gd-Fe-Co 25
5 SF TAMR (AFC) SF TAMR M-H 2m =mm s th s /2(2m-1) M s t H s J Co,AFC Ru [Co/Ru] 20 J M-H Co Co Co Co Co Co M-H Co Ru Co [Co/Ru] 20
1) ( BP No.779) p194-203 2) A.Inomata, B.R.Acharya, E.N.Abarra, A.Ajan, D.Hasegawa, and I.Okamoto,:J. Appl. Phys., 91,7671(2002) 3),,,, MR2004-64, pp.13-18, March 2005 4),,,, MR2005-52, pp.5-9, February 20064) S.S.P.Parkin et al., Phys, Rev. Lett 64, 2304(1990) 5) S.S.P.Parkin et al., Phys, Rev. Lett 64, 2304(1990) 6) S.S.P.Parkin, Phys, Rev. Lett 67, 3598(1991) 7) RE-TM 2007 8) H.Wakabayashi, H.Notarys, J.C.Suits and T.Suzuki,;Mat. Res. Soc. Proc. Vol.150(1989) 9) 2008 10) Gd-Fe-Co 2005 28
1) RE-TM (2006) 2) (2006) 3) [Co/Ru] 20 14pD-8 p.377(2007) 4) 14pD-7 p.376(2007) 5) ( )