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Kitaoka Lab. Shiho Iwai

Kitaoka Lab. Shiho Iwai. arXiv:1008.4298v1(2010). Contents. ・ Introduction ・ High- T c cuprate superconductors 　 ・ YBa 2 Cu 3 O 6+x ・ Method ・ neutron scattering ・ Experimental data ・ Summary. Introduction. High – T c cuprate superconductors. T c (K). HgCaBaCuO

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Kitaoka Lab. Shiho Iwai

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  1. Kitaoka Lab. Shiho Iwai arXiv:1008.4298v1(2010)

  2. Contents ・Introduction ・High-Tccuprate superconductors 　 ・YBa2Cu3O6+x ・Method ・neutron scattering ・Experimental data ・Summary

  3. Introduction High –Tccuprate superconductors Tc (K) HgCaBaCuO （under high pressure） 160 160 HgCaBaCuO （under high pressure） HgCaBaCuO TlCaBaCuO TlCaBaCuO BiCaSrCuO 100 100 YBaCuO 80 liquid nitrogen 60 LaSrCuO Nb3Ge V3Si LaBaCuO NbN NbC Pb Nb-Al-Ge Nb3Sn Hg Nb 0 (year) 0 1911 1986 1910 1990

  4. Introduction La3+2-xSr2+xCuO4 Cu2+x (3d8) Hole doping Cu2+ Cu2+x ; Sr2+ ; La3+ substitute Carrier doping system La2CuO4 d(x2-y2) Cu+2 (3d9) CuO2 layer Sr La2-xSrxCuO4 (LSCO)

  5. Introduction Cu2+ Cu2+x ; Sr2+ ; La3+ substitute Phase diagram CuO2 layer Sr

  6. Introduction YBa2Cu3O6+x(YBCO6+x) YBa2Cu3O6+x CuO-chain O Optimally dope Tc,max=92K ↓ CuO2 plane ？ CuO2 plane How does the ground state change from antiferromagnetismto superconductivity? YBCO6 YBCO6+x YBCO7

  7. Method Neutron scattering Neutron X-ray →　Lattice constant →　Magnetic structure

  8. Method Neutron scattering Magnetic scattering YBCO6+x x=0.15 ←Antiferromagnetism Antiferromagnetism Ef Ei ΔE=Ef-Ei (E=ℏω) QAFM=(0.5,0.5)

  9. c a b Method Samples x=0.45 x=0.35 x=0.3

  10. Experimental data YBCO6.15 x=0.15 (AFM) Q=(0.5 , 0.5) Intensity x=0.35 Doping dependence E(=ℏω) quasielastic peak E～0 →ω～0 inelastic component E=ℏω quasielastic peak →static magnetic order T=2K →superconductivity →the spatial character of magnetic correlations ?

  11. Experimental data Doping dependence incommensurate (0.5±δ , 0.5±δ) incommensurate : 格子と非整合 a* Q=(H,0.5) Q=(0.5,K) x=0.45 CuO2 plane b* x=0.35 (0.5 , 0.5) commensurate x=0.3 commensurate : 格子と整合

  12. Experimental data Doping dependence 2δ δ increase with increasing p

  13. Experimental data x=0.15 x=0.15 Temperature dependence x=0.35 x=0.35 TM～40K unusual AFM order

  14. Experimental data TM In underdoped YBCO incommensurate ＋ unusual antiferromagnetic order This magnetic order coexists superconductivity

  15. Summary TM Superconductivity and this magnetic order can coexist.

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