Transcription of 1.3 宏观物质的磁性 体
1 70 70 . 19 <0 <<1 1. Diamagnetism) He Ne Ar Kr Xe Si Ge S P Cu Ag Au NaCl KBr H2 CO2 CH4 Bi Ga Zn Pb =-1 p25 CGS CGS 10-6 cm3 mol-1 10-6 SI 4 10-5 Kittel 2002 n 4 10-6 (1953) p74 20 C CGS 6(10 ) 6(10 ) 19 0< <<1 - Curie-Waiss)
2 CT =ppCCTTTT C Tp - 2. Paramagnetism Mn Cr W La Nd Pt Pa MnSO4 FeCl3 FeSO4 Gd2O3 Li Na K Ru Cs Mg Ca Sr Ba HCl NO O2 1. >>0 2. 3. TC - 4. 5. M H 100 pCTT 051010 3. Ferromagnetism) Fe-Ni (Permalloy ), Fe-Si, Fe-Co, AlNiCo, CrO2, EuO, GdCl3, 4 Kittel 8 p227 p52 Ms(0 K)=ngJJ B 1936 Neel 1938 1949 4.
3 Antiferromagnetism) P9 ()TK1 CT Neel - =pCTT TpTp TCBa2 LnSbO6and Sr2 LnSbO6(Ln=Dy, Ho, Gd) double perovskites: Lanthanides in the geometrically frustrating fcc latticeKarunadasa et al. PNAS, Vol. 100, P8097 (2003).? FeO, MnO, NiO, CoO, Cr2O3,FeCl2, FeF2, MnF2,FeS, MnS 1938 MnO 122 K Kittel 2005 p236 Tp Fe3O4 30 40 1948 Neel 5. Ferrimagnetism) Fe3O4, MnFe2O4, CoFe2O4 A3Fe5O12, (A=Y,Sm,Gd,Dy,Ho,Er,Yb ) BaFe12O19, PbFe12O19, SrFe12O19, LaFeO3( ) 1.
4 1950 20 50 2. 1040 K 1010Pa bcc hcp, 20 70 20 70 Gd T< 221 K, 221 K< T<228 K 6. (Helimagnetism)Multiferroics: noncollinear spin-spiral systems p115 (1~10 nm) 7.
5 Superparamagnetism Superpara-:High MS, no MR;Para-? 8. p117 , 9. p17 p11) P9 Kittel 2005 / 1~105 1. 2. 3. 4. - 5. 6. 7. 8. maxsaM ,,rrcBMHcTmax()BH . M = 0 1. Ms a msMMs M0 2. 00,0maxmax01lim1()aHHBHBH B-H 0()BMH B Mr Hc3.
6 B-H M-H Hm 42 Oe 4. / - p50cTT cTT cTT CTC 354Ms(0 K)=ngJJ B Kittel p224 p406 TpTC BH max5. B-HcurveBH-Bcurve p210-214 1 J H , J H 0 LJH 000dsin dcoscosHFLJHJHJH 02 0cosHFJHJHMH HJFmH FmH m m 6. 2 / effexdHHH dHNM N M qm& HHexJ/MHd++++---- effHeffexHHNM dxxxdyyydzzzHNMHNMHNM 1xyzNNN CGS 4abcNNN 13abcabcNNN 0,1 2cababcNNN ,1 0cababcNNN 000ddJMdddFHJHM.
7 20001d2 MdFNMMNM N HexHexMM < >p19 p20 131tan3xdNHNM 1 Fe,Co,Ni,Gd 2 Fe-Ni;Fe-Co;Fe-Si; MnBi;ZrZn2; Mn-Cu-M(=Sn,Al,Ge,Zn, .. 3 EuO,CrO2, RMnO3, 4 7. 1 2 (BH)max 3 MRAM) 4 5 8. U, F, G p,T,V,S H, M p19-24.
8 11110000020100ddd1 =d2 BHMmMAHBHHHMHHM 0dmAHM 0dd = dddUTSATSPVHM (d0)S (d0)V ( p21)0dddMMUHTSTTMTT . 0dddd dddFUTSFUTSSTSTPVHM 0d = dddUTSPVHM 0 MTFSTFHM M-H ( , )FMT . 000ddddddGFPVHMGFPVVPMHHM 0ddddFSTPVHM ddddoGSTMHVP ,0,, HPTPTHGSTGMHGVP G, . 0 GFMH 00ddddGFMHHM 0ddddFSTPVHM 0ddddGSTMHPV ,0,, HVTVTHGSTGMHGPV G, F G F G dQTdSHdMpdVdQdU 0 HdMpdVTdSdU0 HMpVTSUGHMTSUF00 MdHVdpSdTdGMdHpdVSdTdF00 lnnBkTnnBZgeGkTZ n ng 001lnBGkTMZHH 0lnBMkTZHHH.
9 P45 5 Fe -Fe bcc a= nm g/cm3 56 g/mol HS~42 Oe Ni fcc a= = g/cm3 emu/g SI
