1 / 82

 Chemistry Faculty. University of Valencia

 Mediterranean Sea.  Chemistry Faculty. University of Valencia. New molecular paramagnetic semiconductors, metals and superconductors Carlos J. Gómez-García Molecular Science Institute. Univ. of Valencia (Spain). Outline. Strategy towards multifunctional molecular materials

evita
Télécharger la présentation

 Chemistry Faculty. University of Valencia

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1.  Mediterranean Sea  Chemistry Faculty. University of Valencia New molecular paramagnetic semiconductors, metals and superconductors Carlos J. Gómez-García Molecular Science Institute. Univ. of Valencia (Spain)

  2. Outline • Strategy towards multifunctional molecular materials • Hystorical background • ET salts with [M(ox)3]3- anions • BEST salts with [M(ox)3]3- anions • Conclusions

  3. Molecule A Molecule B Property A Property B Both properties Multifunctional Molecular materialsStrategy: hybrid approximation Sinergy Cancellation

  4. Multifunctional Materials Electrical Properties Donors + Magnetic anions Optical Properties Magnetic Properties

  5. Outline • Strategy towards multifunctional molecular materials • Hystorical background • ET salts with [M(ox)3]3- anions • BEST salts with [M(ox)3]3- anions • Conclusions

  6. 1954 per2Br 1st molecular metal [Fe(S2CNEt2)2Cl] 1972 1st molecular magnet 1973 (TTF)(TCNQ) 1st organic metal 1st organic SC 1981 (TM-TSF)(ClO4) HISTORY 1984 ET Salts Tc = 12 K multifunctionality 1991 A3C60 Tc = 45 K 1991 (ET)3[CuCl4].H2O 1st paramagnetic metal 1st paramagnetic SC 1995 (ET)4(H3O)[Fe(C2O4)3].PhCN l-(BETS)2[Fe0.5Ga0.5Cl4] 1996 2nd paramagnetic SC 1st metallic ferromagnet 2000 (ET)3[CrMn(C2O4)3]

  7. TM-TTF TTF BET-TTF O BEDO-TTF (BEDO) BEDT-TSF (BETS) Organic donors (cations) S Se BEDT-TTF (ET) BEDS-TTF (BEST)

  8. Molecular magnetic anions [MCl4]- [M(CN)6]3- [Fe(CN)5NO]2- [Fe2(C2O4)5]4- [M(C2O4)3]3-

  9. 7:2 3:1 11:3 7:2 14:4 5:1 1:1 4:1 5:1 4:1 1:1 2:1 3:1 3:1 4:1 4:1 4:1 3:2 4:1 4:1 9:2 2:1 4:1 2:1 2:1

  10. (TTF)4{MII(H2O)2[MIII(C2O4)3]2} [M’(H2O)6]2+ TTF [M(C2O4)3]3- Layered structure

  11. Only known k-type phase with TTF Discrete trinuclear anions [MII(H2O)2[MIII(ox)3]2]4- High Spin trinuclear complex S = 11/2 E. Coronado, C. J. Gómez-García et al. Adv. Mater.1996, 8, 737

  12. (ET)4[(H3O)M(C2O4)3].Solvent FirstParamagneticSuperconductor A. W. Graham, M. Kurmoo, P. Day Chem. Commun. 1995, 2061 BEDT-TTF (ET) [M(C2O4)3]3-

  13. ET4[AM(C2O4)3].D

  14. Ligand(dto,croc,...) Solvent (PhX, PhX2, PhOH,PhCOOH, PhCHO,PhCH3,...) Metal (Co, Mn,…) Cation (A+, Mn2+, Fe2+,... ) Donor(BEST, BEDO,…) Modifications superconductivity + ferromagnetism + optical activity (?)

  15. Outline • Strategy towards multifunctional molecular materials • Hystorical background • ET salts with [M(ox)3]3- anions • BEST salts with [M(ox)3]3- anions • Conclusions

  16. ET4[H3OM(ox)3].PhXMIII = Cr, X = Cl (6) and Br (7) MIII = Fe, X = Cl (8), Br (9) and F (10) BEDT-TTF (ET) [M(ox)3]3-M = Cr and Fe C6H5X (X = F, Cl and Br)

  17. ET4[H3OM(ox)3].PhXMIII = Cr, X = Cl (6) and Br (7) MIII = Fe, X = Cl (8), Br (9) and F (10) 1 mm

  18. 295 K ET4[H3OM(ox)3].PhXM = Cr, X = Cl (6), Br (7) M = Fe, X = Cl (8), Br (9), F (10) Layers parallel to the ab plane b” Phase Isostructural to Day’s salts although with a structural transition below  220 K

  19. 95 K ET4[H3OM(ox)3].PhXM = Cr, X = Cl (6), Br (7) M = Fe, X = Cl (8), Br (9), F(10) Also two different layers but now the layers are not equivalent B B A A B B A A D D C C D D C C

  20. 295 K ET4[H3OM(ox)3].PhXM = Cr, X = Cl (6), Br (7) M = Fe, X = Cl (8), Br (9), F(10) 6.30 Å 6.30 Å 6.39 Å 6.39 Å 6.30 Å 6.30 Å Distorted hexagonal cavity

  21. 95 K ET4[H3OM(ox)3].PhXM = Cr, X = Cl (6), Br (7) M = Fe, X = Cl (8), Br (9), F(10) contraction of four sides of the hexagon 6.30 Å 6.30 Å Distorted hexagonal cavity 6.30 Å 6.21 Å 6.39 Å 6.39 Å 6.33 Å 6.33 Å 6.30 Å 6.30 Å 6.21 Å 6.30 Å

  22. 295 K ET4[H3OM(ox)3].PhXM = Cr, X = Cl (6), Br (7) M = Fe, X = Cl (8), Br (9), F(10) 33.5º Tilted solvent molecule in-plane PhBr molecule 95 K 33.1º Tilted solvent molecule out-of-plane PhBr molecule

  23. Electrical Properties ET4[H3OCr(ox)3].PhCl (6)

  24. Electrical Properties ET4[H3OCr(ox)3].PhCl (6) s300K 10-2 S.cm-1 Metallic down to  120 K Charge localization

  25. Electrical Properties ET4[H3OCr(ox)3].PhCl (6) No SC transition above 0.4 K

  26. Electrical Properties ET4[H3OFe(ox)3].PhCl (8)

  27. Electrical Properties ET4[H3OFe(ox)3].PhCl (8) s300K 8.10-3 S.cm-1 Metallic down to  100 K Charge localization

  28. Electrical Properties ET4[H3OFe(ox)3].PhCl (8) No SC transition above 0.4 K

  29. Electrical Properties ET4[H3OCr(ox)3].PhBr (7)

  30. Electrical Properties ET4[H3OCr(ox)3].PhBr (7) Tc 1.9 K Metallic down to  50 K s300K 10-2 S.cm-1 Chargelocalization

  31. Electrical Properties ET4[H3OCr(ox)3].PhBr (7) onset at Tc 1.9 K zeroresistance at  0.4 K

  32. Electrical Properties ET4[H3OCr(ox)3].PhBr (7) H  layer(ab) T = 0.4 K Hc2||  50 mT Hint 4 mT

  33. Electrical Properties ET4[H3OCr(ox)3].PhBr (7) H  layer(ab) T = 0.4 K Hint 4 mT Hc2||  50 mT

  34. Electrical Properties ET4[H3OFe(ox)3].PhBr (9)

  35. Electrical Properties ET4[H3OFe(ox)3].PhBr (9) Tc 4.0 K Metallic down to  50 K s300K 5.10-3 S.cm-1 Chargelocalization

  36. Electrical Properties ET4[H3OFe(ox)3].PhBr (9) onset at Tc 4.0 K zeroresistance at  1.0 K

  37. Electrical Properties ET4[H3OFe(ox)3].PhBr (9) H  layer (ab)

  38. Electrical Properties ET4[H3OFe(ox)3].PhBr (9) H  layer (ab) Hc2 8 T

  39. Electrical Properties ET4[H3OFe(ox)3].PhBr (9) T = 0.4 K H layer(ab) Hc1 10 mT Hc2 8 T

  40. Electrical Properties ET4[H3OFe(ox)3].PhBr (9) Tc decreases with increasing currents

  41. Electrical Properties ET4[H3OFe(ox)3].PhF (10)

  42. Electrical Properties ET4[H3OFe(ox)3].PhF (10) Tc 1.2 K Chargelocalization s300K 102 S.cm-1 Metallic down to  250 K

  43. Electrical Properties ET4[H3OFe(ox)3].PhF (10) onset at Tc 1.2 K zeroresistance at T < 0.4 K

  44. Electrical Properties ET4[H3OFe(ox)3].PhF (10) H  layer (ab) Hc2> 2 T

  45. Electrical Properties ET4[H3OFe(ox)3].PhF (10) H  layer (ab) T = 0.4 K Hc2 4 T Hint 5.5 mT

  46. Electrical Properties ET4[H3OM(ox)3].PhX

  47. Magnetic Properties ET4[H3OM(ox)3].PhX Pauli Paramagnetism (TIP) + Paramagnetism (M)

  48. Magnetic Properties ET4[H3OFe(ox)3].PhBr (9) Hc1 10 mT Tc = 4.0 K Meissner Effect

  49. Magnetic Properties ET4[H3OFe(ox)3].PhBr (9) AC susceptibility (in-phase signal) Hc1 10 mT Meissner Effect

  50. Magnetic Properties ET4[H3OFe(ox)3].PhBr (9) Hc1 10 mT Tc = 4.0 K AC susceptibility (out-of-phase signal)

More Related