ESR study of the electronic properties of the new organic conductors κ-(BEDT-TTF)2Cu[N(CN)2]X, X = Br; I

Kataev, V.; Winkel, G.; Knauf, N.; Gruetz, A.; Khomskiî, D. I.; Wohlleben, D.; Crump, W.; Hahn, Josef; Tebbe, K.‐F.

doi:10.1016/0921-4526(92)90616-z

Cited by 23 publications

(13 citation statements)

References 33 publications

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“…Our data measured on slow cooling corresponded closely to that previously reported. [11][12][13][14][15] The only notable difference was a small gradual decrease in on cooling from room temperature to 100 K, similar to that in static susceptibility measurements. 3 The general idea behind the thermal cycles used was to alter the degree of ethylene ordering.…”

Section: Methodssupporting

confidence: 56%

“…In normal metal is independent of temperature ͑Pauli spin susceptibility͒, reflecting constant density of states at the Fermi level. In contrast, temperature dependent was found in the Br salt by static 3 and ESR measurements, [11][12][13][14][15] the origin of which is not clear at present. The reported (T) measurements, however did not take into account the possible influence of the phase transformations, which are sensitive to the thermal cycle.…”

Section: Introductionmentioning

confidence: 99%

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ESR study of the ordering transformation inκ−(BEDT−TTF)

et al. 2000

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Ordering transformation and its effect on the electronic structure of the -͑BEDT-TTF͒ 2 Cu͓N͑CN͒ 2 ͔Br organic superconductor was studied by measuring annealing induced changes in low temperature ESR spectra and spin susceptibility temperature dependence. The transformation is shown to proceed through coexistence of two phases. Besides resistivity decrease, ordering was shown to increase ESR spin susceptibility ͑below about 160 K͒ with a tendency for restoration of the temperature independent Pauli term. Gaplike spin susceptibility behavior below 60 K is shown to develop only at some stage of ordering. These effects point to a relationship between temperature dependent spin susceptibility in the salt and incomplete ordering.

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Section: Methodssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

ESR study of the ordering transformation inκ−(BEDT−TTF)

et al. 2000

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“…By contrast, spin relaxation in κ-(ET) 2 Cu(NCS) 2 , which exhibits no anomalous Nernst effect, shows single exponential time dependence. The temperature range T C < T < 30 K encompasses several phenomena observed in the κ-(ET) 2 X family, including changes in conduction electron spin resonance [15], electronic phase separation [16,17] and the onset of antiferromagnetic order κ-(ET) 2 Cu[N(CN) 2 ]Cl at T Neel = 27 K [18]. We discuss similarities to La 2-x Sr x CuO 4 where experiments have also demonstrated stretched exponential relaxation [19] and a Nernst signal far above T C [5,6].…”

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confidence: 99%

Stretched exponential spin relaxation in organic superconductors

et al. 2013

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“…The spin susceptibility between 300 and 16 K was fitted with the Curie-Weiss equation 2, . 40 It is well established that the DH pp magnitude depends on the spin-orbit coupling and dipolar interactions, which cause broadening, and magnetic exchange, which affords sharpness. 42,43 These factors explain the linewidth behavior for in the form of the c M T versus T plot, being c M the molar magnetic susceptibility.…”

Section: A T T E M P T S T O O B T a I N S I N G L E C R Y S T A L S mentioning

confidence: 99%

“…In agreement with the results from the literature, 20 the signal is typically of Cu II (located spins, S = 1/2) superposed to the signal of ttf Figure 8 shows the thermal dependence of the EPR normalized spin susceptibility, c T / c 300 = (DH pp ) 2 I, where DH pp is the peak-to-peak linewidth and I is the amplitude of the signal. 40 It is important to note that the Lorentzian fitting is dominated by the Cu II signal. The spin susceptibility between 300 and 16 K was fitted with the Curie-Weiss equation 2, (2) where C = S(S + 1) N g 2 b 2 / 3 k B , and q is the nonzero Weiss term or Weiss constant.…”

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confidence: 99%

A new molecular magnetic semiconductor based on tetrathiafulvalene (ttf) and oxamato ligand (opba): [ttf]2[Cu(opba)]·H2O

Dias¹,

Stumpf²,

Mambrini³

et al. 2010

J. Braz. Chem. Soc.

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. As propriedades magnéticas (dc) mostram um valor do produto c M T na temperatura ambiente próximo ao esperado para três spins S = ½ desacoplados e um valor de 0.13 emu K mol -1 a baixas temperaturas (4 K). A curva do produto c M T versus T foi ajustada e o melhor modelo consiste de um termo para o dímero (ttf •+ ) 2 (Bleaney-Bowers, resultando em J 2 = -186 cm ).An oxamato-based compound of formula [ttf] 2 [Cu(opba)]·H 2 O, with ttf = tetrathiafulvalene and opba = ortho-phenylenebis(oxamato), has been prepared and characterized. The complex was obtained by metathesis from (ttf) 3 (BF 4 ) 2 and (Bu 4 N) 2 [Cu(opba)] in acetonitrile at room temperature. The UV-Vis-NIR spectrum reveals the presence of the radical cation in two forms, (ttf Keywords: tetrathiafulvalene, molecular magnetism, semiconductor, oxamato ligand, molecular spintronics IntroductionIn the last few decades, the search for a molecular equivalent of a given material has increased, owed to the possibility to incorporate a new property through organic or coordination compounds maintaining the features of the original system. In the area of electronic materials, for example, molecular conductors constitute a theme of large appeal, where ttf (tetrathiafulvalene, 2,2'-bi-1,3-dithiole) and its derivatives are by far the most investigated. Ttf is a π-electron donor capable to form radical [ttf 2 In Dias et al. 1275 Vol. 21, No. 7, 2010 1973, the first 1D metal [ttf-tcnq] (with tcnq = tetra-cyanop-quinodimethane) was described.3 Its structure consists of stacks of either the tcnq or ttf planar molecules and there is a partial electron transfer from the donor to the acceptor forming the charge-transfer salt [ttf] δ+ [tcnq] containing organic radicals and paramagnetic coordination compounds are found in the literature. The stacking of multilayers is the topological feature of the devices that already use the GMR or MTJ technologies with magnetic control of the flow of spin-polarized electrons. Indeed, a molecular construction of each thin layer with specific properties, promoting tailored interlayer interactions or maintaining isolation through organic or inorganic spacers represents a significant challenge to synthetic chemists.Our group has worked with several planar building blocks and organic radicals that show the capability to form 2D networks, negatively or positively charged, which are candidates to contribute to the development of a molecular branch of spintronics. Recently, a magnetic molecular semiconductor based on a dithiolene ligand derivative and the nitronyl nitroxide radical cation was presented. 24Herein we report the synthesis and properties of the first molecular semiconductor with the tetrathiafulvalene cation and a paramagnetic oxamato-based complex of formula Experimental Physical measurementsInfrared spectra were obtained by using a Fourier transform infrared spectrometer Galaxy 3030 model (Mattson Instrument) with DTGS (deuterated triglycine sulphate) detector on KBr pellets. The UV-Vis-NIR absorption spectra were mea...

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ESR study of the electronic properties of the new organic conductors κ-(BEDT-TTF)2Cu[N(CN)2]X, X = Br; I

Cited by 23 publications

References 33 publications

ESR study of the ordering transformation inκ−(BEDT−TTF)

ESR study of the ordering transformation inκ−(BEDT−TTF)

Stretched exponential spin relaxation in organic superconductors

A new molecular magnetic semiconductor based on tetrathiafulvalene (ttf) and oxamato ligand (opba): [ttf]2[Cu(opba)]·H2O

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