ao 2T( ax 设磁畴宽度D〓,在单位体积内将有2/D个畴和畴壁数目,因而单位体积内畴壁面积 1×1) 应为 4 将(23)代入(1,可得x-90÷4材2 1x=x1 42M2+3xx5 13.证明:用单弛豫来描述磁场为交变磁场强度H=Hne"作用下 磁感应强度为B=Bne) dB (Bm-B)=ioB dt t B (ia+-B Bm=bou H=Hou Hme B=地0bnea H 1+ior 1+(r) 由B=0HH=0(4-i)Hne....................(2) 2 ( ) 2 cos 2 2 sin 0 0 0 ( ) 0 x l x x l l l x x x           =   =    = =  设磁畴宽度 2 l D = ,在单位体积内将有2/D个畴和畴壁数目,因而单位体积内畴壁面积 应为 ........................(3) 4 2 4 (1 1) l S D l  =   = ⊥ 将(2)(3)代入(1),可得: 0 2 0 90 3 4      s s i M − = 0 0 0 2 2 0 0 0 2 0 90 90 3 4 3 1 / 3 4 1 1                   s s s s s r i i r M M +  =  = + = + =  = − − − 13. 证明: 用单弛豫来描述,磁场为交变磁场强度 i t m H H e  = 作用下 磁感应强度为 i( t c) m B B e  − = 2 0 0 0 0 1 ( ) (1 ) 1 ) 1 ( ( ) 1                    + − = + = = =  + =  = − = i t i m i t i m i t m i i m m m i H e i H e B B H H e B i B B B i B dt dB  由 i t m B H i H e     (' ' ') = 0 = 0 −