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VI.
. , . . . . . .

T

=


i

Mi = 0 .

, . , = 0 = 0, . "" , "" , .. () (.6.1). ( ). , . , . 6.1. : ) =0, ) , ) . ) , , , . , . (1919.) ­ (.6.1). , ( . 6.2. ) , (. 6.2). , , Mr. : I - ( ), II - , III- (.6.1), 3


, IV - , . .. (1938.), .. : - Ms, Bs; (remanence) - Mr, Br; - H; - E
M loss

=


0

1

HdM .

(6.1)

: : Hc<800A/m50Oe. : Hc>800A/m50Oe. . . , , ( ) , . , , . : 1) - UM 2) - U0, 3) - U, 4) - UK, 5) U , 6) U,. (6.2) U= UM +U0+ U +UK+U+U. , . (6.2). 1) - UM, , - . (1.13) UM= -MH (6.3) 2) - U0. U0 , . , (1/8) B2 dV ~ Ms2 106 /3, Ms . U0 = NPMs2/2 , (6.4) NP - . , . , , . 6.3,,, , , [1]: Ua)0.85MS2d; U)0.53MS2d; U)0.374MS2d, ( ) (6.5) , , . 6.4. MS=1.7·103 U0.85d3·106 /3. . 6.3. . 6.4.

. 4


U = -


ij

rr J ij ( Si S j ) ,

(6.6)

( ) - UK. . , -Fe [100] - , [111] ­ , Ni - (. 6.6). "" - [1000] ( ), "" .6.6. -Fe, Ni, ( ). Co (.6.7). - , , . , "" L-S-. , , , . . .6.3.

.6.5.

U Jij - . , .6.5. , , , U0. , .6.5 ­ . , , (5.3) . 2.

UK =


n

K n

2n

,

(6.7)

= cos - . , .. - , n , . (6.8) UK=K0+K1cos2+K2cos4. 1 <0, K2 =0 , min (UK) =0. , ( 12 + 22 +32 1) (6.9) UK=K0+K1(1222+2232+3212)+K2122232 . ( /3) 6.1: 6.1. Fe, Ni, Co 1 , /3 (/3) 2 , /3 (/3) 4 5 Fe 4.6 10 ( 4.6 10 ) -0.075 104 (-0.075 105) 3 4 Ni -5.7 10 (5.7 10 ) -2.3 103 (-2.3 104) 5 6 5 Co 4.1 10 (4.1 10 ) 1.0 10 (1.0 106) 5


, , , , , , .. - , , , .. , . , .. , . : . , , . , , (6.10) UK, =K cos, - . Fe Ni UK, ~ 0.1 -1 /2. 3. -U. - . Ni - , Fe - . l/l=S - . , , , , ijM, : M (6.11) ij = ijkl k l .


k ,l

ijkl 0 0 0 - [100]/ 2 - [100]/ 2 [100] - [100] - [100]/ 2 0 0 0 [100]/ 2 (6.12) - [100]/ 2 - [100]/ 2 [100] 0 0 0 0 0 3 / 4 [111] 0 0 0 0 0 0 0 3 / 4 [111] 0 0 0 0 0 3 / 4 [111] 0

[100]



[111]

.

[100]=[111]=, , . , =(2[100]+3[111])/5 (6.13) 6 -6 Fe[100]=19.5 10 [111]= - 18.8 10 , , =-3.48 10-6 U=ES2/2, (6.14) E - . . [100] [-100] , .. S (. 6.4), . 3- , (.6.4). , 2- , .. [010]. [010], , [100]. . . . , , (.6.4). 4. - U. - . ij 6


U = -ij ijM.

(6.15)

, . yz (. 6.5), . . 6.6 1800 , .. . : (6.16) E=-JS(-S) - [-JS2] = 2JS2 . 6.6. . (. 6.6) , n, /n. E = -Js2cos(/n), E = n[-JS2cos(/n)-(-JS2)] = nJS2[1-cos(/n)] (6.17) n>>1 (6.18) E JS22/n. (6.18) , : . , EK n. Fe 150a (- ): (6.19) Wwall 2 JS2 /na2 + Kna. , Wwall 1 erg/cm2. W/n = -2JS2/2n2a2+Ka = 0. , (6.20) n = (2JS2/2Ka3)1/2, , , = na = (2JS2/Ka)1/2 = (A/K)1/2 = 0, (6.21) A = JS2/a (6.21) - , =2(JKS2/a)1/2=2(AK)1/2=20. (6.21) , ( ) , - ( )/() 0. . . . , , , (.6.7). , ? , . (. -)/() , . , U0=NPM2/2 (6.22) M - () , . 6.7. : . 6.7 () NPBl =4/(+h) (6.23). () : NPNeel=4h/(h+), (6.23) h . M2 MMs/2, 0 = U0 (6.24) 0Bl=2/(h+) Ms2 , (6.24) 0Neel=h/(h+) Ms2.
P P

7


, h< . , Fe, Ni, h<103A0 . : = perm(eabiliti)+alloy - Ni-Fe+Cu/Cr/Mo/Mn. . (sendust):-Fe+9.5%Si+5.5%Al . .6.8, 6.9 [2]. , 80 . , . 6.9.

.6.8. , , , [2], [3] [4]
1. C. Kittel, 2. T. Trunk to Neґ el 3. Hubert, 4. Loo

.

.6.9. : , , .

: Rev. Mod.Phys. v.21 (1949)541 et al, «Domain wall structure in Permalloy films with decreasing thickness at the Bloch transition» J.Appl. Phys., 89(2001)7606-7

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