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Comment on "specific Raman signatures of a dimetallofullerene peapod".

Phys Rev Lett 93:26 Pt 1 (2004) 269601

Authors:

David A Britz, Andrei N Khlobystov, G Andrew D Briggs, Arzhang Ardavan
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Comment on "specific Raman signatures of a dimetallofullerene peapod"

Physical Review Letters 93:26 I (2004)

Authors:

DA Britz, AN Khlobystov, G Andrew, D Briggs, A Ardavan, A Débarre, R Jaffiol, C Julien, D Nutarelli, A Richard, P Tchénio
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A new mechanism for electron spin echo envelope modulation

(2004)

Authors:

John JL Morton, Alexei M Tyryshkin, Arzhang Ardavan, Kyriakos Porfyrakis, Stephen A Lyon, G Andrew D Briggs
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Fermiology of new charge-transfer salts, β″-(BEDT-TTF) 4[(H3O)M(C2O4)3]-solvent where M = Ga, Cr and Fe

Journal De Physique IV JP 114 (2004) 205-209

Authors:

AI Coldea, AF Bangura, A Ardavan, J Singleton, A Akutsu-Sato, H Akutsu, SS Turner, P Day

Abstract:

We report high-field magnetotransport measurements on β″-(BEDT- TTF)4[(H3O)M(C2O4) 3]· solvent, where M=Ga3+, Cr3+ and Fe3+ and solvent=C5H5N. In spite of their differing transition metal-ions, M, the three compounds exhibit similar magnetic quantum oscillation spectra superimposed on a positive magnetoresistance. At least four independent quantum oscillation frequencies have been identified, corresponding to two different hole and electron pockets of the Fermi surface which follow the rules of a compensated metal. Observation of the small pockets could be the result of the Fermi surface reconstruction induced by a possible density wave. The effective masses are very similar for different samples and for different pockets range between meff ≈ 0.5-1.1 me whereas the Dingle temperatures varies between TD ≈ 1.4-4 K. At low temperature, the longitudinal magnetoresistance violates Kohler's rule, suggesting that the interlayer transport in these quasi-2D systems cannot be related to a single scattering time and that the disorder plays an important role. © EDP Sciences.
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The effect of magnetic ions and disorder on superconducting β″-(BEDT-TTF)4[(H3O)M(C2O 4)3]· C6H5NO2 salts, where M = Ga and Cr

Journal De Physique IV JP 114 (2004) 285-287

Authors:

AF Bangura, AI Coldea, A Ardavan, J Singleton, A Akutsu-Sato, H Akutsu, P Day

Abstract:

We report magnetotransport measurements performed in magnetic fields of up to 33 T and at low temperatures (0.45 K4[(H3O)M(C2O4)3]· C6H5NO2, where the 3d metal ion M is either non-magnetic Ga3+ or magnetic Cr3+, Quantum oscillations suggest that the salt with M = Ga has two two-dimensional Fermi surface pockets (45 T and 230 T) whereas when M = Cr only one pocket (230 T) is observed. Replacing Ga with Cr has the effect of enhancing the effective mass of the 230 T pocket from 1.2 ± 0.2 me to 2.2 ± 0,3 me and reducing the superconducting critical temperature from Tc ≈ 8 K to Tc ≈ 5 K. © EDP Sciences.
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