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Electron Spin Resonance study of organic conductors

English title Electron Spin Resonance study of organic conductors
Applicant Forro Laszlo
Number 124723
Funding scheme Project funding
Research institution Laboratoire de nanostructures et nouveaux matériaux électroniques EPFL - SB - IPMC - LNNME
Institution of higher education EPF Lausanne - EPFL
Main discipline Condensed Matter Physics
Start/End 01.04.2009 - 31.03.2012
Approved amount 189'588.00
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Keywords (13)

nanotubes; organic conductors; superconductivity; solid state physics; ESR; CESR; electron spin resonance; organic metals; low-dimensional conductors and superconductors; Mott-transition; carbon nanotubes; high pressure ESR; high frequency ESR

Lay Summary (English)

Lead
Lay summary
Electron Spin Resonance (ESR) is a very efficient technique for studying organic conductors because of its high sensitivity and the narrow lines due to the weak spin-orbit coupling of the constituent light elements. It is suitable to study organic semiconductors and metals. Conduction Electron Spin Resonance (CESR) is a direct method to measure the conduction electron spin susceptibility. Since CESR probes directly the electrons around the Fermi surface, even slight changes in the low energy states can cause marked and easily detectable variations in the spectra.We wish to apply these techniques for few model compounds to investigate the effect of pressure on the physical properties through the modification of the i) dimensionality; ii) the overlap integrals (bandwidth); iii) the electron-electron and iv) electron-phonon interactions. Last but not least pressure will have a profound effect on phase transitions, both of magnetic and non-magnetic origins. Furthermore, variable frequency range is very useful in studying the dimensionality of the electronic structure and magnetic interactions in these conductors, since the spin relaxation rate will be markedly frequency dependent in these cases.The systems which we plan to investigate are 1. kappa-(BEDT-TTF)2Cu[N(CN)2]Cl, and related superconducting charge transfer salts;. 2. Organic Kagome compound (EDT-TTF-CONH2)6[Re6Se8(CN)]6; 3. (EDT-TTF-I2)2(diiodo-fumarates) and zwitterions. 4. Single-walled carbon nanotubes (SWNTs).
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Magnetic fluctuations above the Neel temperature in kappa-(BEDT-TTF)(2)Cu{[}N(CN)(2)]Cl, a quasi-2D Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interaction}
Antal Agnes, Feher Titusz, Nafradi Balint, Forro Laszlo, Janossy Andras (2012), Magnetic fluctuations above the Neel temperature in kappa-(BEDT-TTF)(2)Cu{[}N(CN)(2)]Cl, a quasi-2D Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interaction}, in PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 249(5), 1004-1007.
Dual {[}proton]/{[}hole] mixed valence in a molecular metal: balancing chemical activity in the solid state by tapping into a molecular hole reservoir}}
Lakhdar Youssef, Meziere Cecile, Zorina Leokadiya, Giffard Michel, Batail Patrick, Canadell Enric, Auban-Senzier Pascale, Pasquier Claude, Jerome Denis, Nafradi Balint, Forro Laszlo (2011), Dual {[}proton]/{[}hole] mixed valence in a molecular metal: balancing chemical activity in the solid state by tapping into a molecular hole reservoir}}, in JOURNAL OF MATERIALS CHEMISTRY, 21(5), 1516-1522.
Pressure and temperature dependence of interlayer spin diffusion and electrical conductivity in the layered organic conductors kappa-(BEDT-TTF)(2)Cu{[}N(CN)(2)]X (X = Cl, Br)}
Antal Agnes, Feher Titusz, Tatrai-Szekeres Erzsebet, Fueloep Ferenc, Nafradi Balint, Forro Laszlo, Janossy Andras (2011), Pressure and temperature dependence of interlayer spin diffusion and electrical conductivity in the layered organic conductors kappa-(BEDT-TTF)(2)Cu{[}N(CN)(2)]X (X = Cl, Br)}, in PHYSICAL REVIEW B, 84(7), 1-5.
A Neutral Zwitterionic Molecular Solid
El-Ghayoury Abdelkrim, Meziere Cecile, Simonov Sergey, Zorina Leokadiya, Cobian Manuel, Canadell Enric, Rovira Carme, Nafradi Balint, Sipos Balazs, Forro Laszlo, Batail Patrick (2010), A Neutral Zwitterionic Molecular Solid, in CHEMISTRY-A EUROPEAN JOURNAL, 16(47), 14051-14059.
Measurement of interlayer spin diffusion in the organic conductor kappa-(BEDT-TTF)(2)Cu{[}N(CN)(2)]X, X = Cl, Br}
Antal Agnes, Feher Titusz, Nafradi Balint, Gaal Richard, Forro Laszlo, Janossy Andras (2010), Measurement of interlayer spin diffusion in the organic conductor kappa-(BEDT-TTF)(2)Cu{[}N(CN)(2)]X, X = Cl, Br}, in PHYSICA B-CONDENSED MATTER, 405(11, S), 168-171.
Origin of the ESR spectrum in the Prussian blue analog RbMn{[}Fe(CN)(6)]center dot H2O}
Antal A., Janossy A., Forro L., Vertelman E. J. M., van Koningsbruggen P. J., van Loosdrecht P. H. M. (2010), Origin of the ESR spectrum in the Prussian blue analog RbMn{[}Fe(CN)(6)]center dot H2O}, in PHYSICAL REVIEW B, 82(1), 1-5.
Publisher's Note: Origin of the ESR spectrum in the Prussian blue analog RbMn{[}Fe(CN)(6)]center dot H2O (vol 82, 014422, 2010)}
Antal A., Janossy A., Forro L., Vertelman E. J. M., van Koningsbruggen P. J., van Loosdrecht P. H. M. (2010), Publisher's Note: Origin of the ESR spectrum in the Prussian blue analog RbMn{[}Fe(CN)(6)]center dot H2O (vol 82, 014422, 2010)}, in PHYSICAL REVIEW B, 82(1), 1-5.
Size dependence of the magnetic response of graphite oxide and graphene flakes - an electron spin resonance study
Ciric Luka, Sienkiewicz Andrzej, Djokic Dejan M., Smajda Rita, Magrez Arnaud, Kaspar Tommy, Nesper Reinhard, Forro Laszlo (2010), Size dependence of the magnetic response of graphite oxide and graphene flakes - an electron spin resonance study, in PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 247(11-12), 2958-2961.
Spin dynamics in the S=1/2 antiferromagnetic chain compounds delta-(EDT-TTF-CONMe2)(2)X (X=AsF6, Br): A multifrequency electron spin resonance study
Nafradi Balint, Olariu Areta, Forro Laszlo, Meziere Cecile, Batail Patrick, Janossy Andras (2010), Spin dynamics in the S=1/2 antiferromagnetic chain compounds delta-(EDT-TTF-CONMe2)(2)X (X=AsF6, Br): A multifrequency electron spin resonance study, in PHYSICAL REVIEW B, 81(22), 1-7.
Multifrequency ESR in ET2 MnCu{[}N(CN)(2)](4): A radical cation salt with quasi-two-dimensional magnetic layers in a three-dimensional polymeric structure}
Nagy K. L., Nafradi B., Kushch N. D., Yagubskii E. B., Herdtweck E., Feher T., Kiss L. F., Forro L., Janossy A. (2009), Multifrequency ESR in ET2 MnCu{[}N(CN)(2)](4): A radical cation salt with quasi-two-dimensional magnetic layers in a three-dimensional polymeric structure}, in PHYSICAL REVIEW B, 80(10), 1-6.
Towards electron spin resonance of mechanically exfoliated graphene
Ciric Luka, Sienkiewicz Andrzej, Nafradi Balint, Mionic Marijana, Magrez Arnaud, Forro Laszlo (2009), Towards electron spin resonance of mechanically exfoliated graphene, in PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, 246(11-12, SI), 2558-2561.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved


Awards

Title Year
Member of the Croatian Academy of Sciences 2010

Associated projects

Number Title Start Funding scheme
113399 Electron Spin Resonance study of organic conductors 01.12.2006 Project funding
113399 Electron Spin Resonance study of organic conductors 01.12.2006 Project funding
144419 Electron Spin Resonance Study of Organic Conductors 01.10.2013 Project funding

Abstract

Electron Spin Resonance (ESR) is a very efficient technique for studying organic conductors because of its high sensitivity and the power to resolve the narrow lines due to the weak spin-orbit coupling of the constituent light elements. It is suitable to study organic semiconductors and metals. Conduction Electron Spin Resonance (CESR) is a direct method to measure the conduction electron spin susceptibility, cs. Since CESR probes directly the electrons around the Fermi surface, even slight changes in the low energy states can cause marked and easily detectable variations in the spectra.In the first phase of the project (the elapsed 4 years) we have built and tested a highly original Electron Spin Resonance spectrometer in a quasi-optical bridge configuration, which operates at frequencies up to 420 GHz. This set-up enabled us to easily implement high-pressure ESR measurements, as well. This spectrometer, together with our conventional spectrometers at 4, 9 and 35 GHz, with their high-pressure options represent a unique experimental assembly for studying the basic physical properties of organic conductors.In the second phase we wish to apply these techniques for few model compounds to investigate the effect of pressure on the physical properties through the modification of the i) dimensionality; ii) the overlap integrals (bandwidth); iii) the electron-electron and iv) electron-phonon interactions. Last but not least pressure will have a profound effect on phase transitions, both of magnetic and non-magnetic origins. Furthermore, variable frequency range is very useful in studying the dimensionality of the electronic structure and magnetic interactions in these conductors, since the spin relaxation rate will be markedly frequency dependent in these cases.The systems which we plan to investigate are 1. kappa-(BEDT-TTF)2Cu[N(CN)2]Cl, and related superconducting charge transfer salts;. 2. The organic Kagome compound (EDT-TTF-CONH2)6[Re6Se8(CN)]6; 3. (EDT-TTF-I2)2(diiodo-fumarates) and zwitterions. 4. Single-walled carbon nanotubes (SWNTs).
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