Magnetic susceptibility, heat capacity, and optical conductivity of LiPc and LiPcI

Dumm, M.; Dressel, Martin; Lunkenheimer, P.; Loidl, A.; Weiden, M.; Steglich, F.; Aßmann, B.; Homborg, H.; Fulde, Peter

doi:10.1007/s100510050555

Cited by 18 publications

(20 citation statements)

References 2 publications

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“…a superlinear increase of σ (ν). It seems reasonable that the UDR and the second universality behavior, which often are observed simultaneously in the same material [30,[32][33][34][35], are separate physical phenomena. Indeed, a closer analysis [28] of the crossover of σ (ν) from DC to the ν n power law in the present data reveals that it is too smooth to be described by the simple ansatz σ = σ DC + σ 1 ν 1.13 .…”

Section: Dielectric Resultsmentioning

confidence: 99%

“…The approach of such a nearly linear increase of σ (ν) (corresponding to a nearly constant dielectric loss, ε ∼ σ /ν) for high frequencies was found in a variety of materials (e.g., Refs. [30][31][32][33][34][35]), including La 1−x Sr x MnO 3 with small x [30], and was termed "second universality" [32]. The develop- ε' ν (Hz) Fig.…”

Section: Dielectric Resultsmentioning

confidence: 99%

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Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO 3

et al. 2001

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The charge-ordered perovskite Pr0.65Ca0.28Sr0.07MnO3 was investigated by means of magnetic susceptibility, specific heat, dielectric and optical spectroscopy and electron-spin resonance techniques. Under moderate magnetic fields, the charge order melts yielding colossal magnetoresistance effects with changes of the resistivity over eleven orders of magnitude. The optical conductivity is studied from audio frequencies far into the visible spectral regime. Below the phonon modes hopping conductivity is detected. Beyond the phonon modes the optical conductivity is explained by polaronic excitations out of a bound state. ESR techniques yield detailed informations on the (H,T ) phase diagram and reveal a broadening of the linewidth which can be modeled in terms of activated polaron hopping. PACS. 63.20.-e Phonons in crystal lattices -71.30.+h Metal-insulator transitions and other electronic transitions -72.60.+g Mixed conductivity and conductivity transitions -78.30.-j Infrared and Raman spectra

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Section: Dielectric Resultsmentioning

confidence: 99%

Section: Dielectric Resultsmentioning

confidence: 99%

Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO 3

et al. 2001

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“…127 However, because of the strong Coulomb repulsion, the system is a 1D Mott-Hubbard insulator with a Hubbard gap of 72 kJ mol -1 as inferred from optical measurements. LiPc has one unpaired electron on the inner ring of the macrocycle.…”

Section: Lithium Phthalocyaninementioning

confidence: 98%

“…The 1D molecular semiconductor lithium phthalocyanine (LiPc) has a half-filled conduction band and is expected to be an organic metal . However, because of the strong Coulomb repulsion, the system is a 1D Mott−Hubbard insulator with a Hubbard gap of 72 kJ mol -1 as inferred from optical measurements.…”

Section: 4 Lithium Phthalocyaninementioning

confidence: 99%

Calorimetric Investigation of Phase Transitions Occurring in Molecule-Based Magnets

2006

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“…1, is almost due to an impurity of the corresponding pc ±/2± component, reflecting the sensitivity of the diphthalocyaninato(2±)metallates of the smaller metal ions towards ring oxidation. 2 c, but the absorption of the`B band' at 14700 cm ±1 is notably diminished, and there is an intense new band at 2070 cm ±1 reflecting the semiconducting properties (r(300 K) » 2±5´10 ±2 X ±1 cm ±1 for [M(pc ± ) 2 ]I 2 (M = Sc, Y)) of these diamagnetic intrinsic molecular electronic conductors [9,11]. 2 Fig.…”

Section: Syntheses and Spectral Characterisationmentioning

confidence: 99%

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Göldner

et al. 2001

Z. anorg. allg. Chem.

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Potassium diphthalocyaninato(2±)metallate(III), K[M(pc 2± ) 2 ] (M = Bi, La, Ce, Pr, Sm, Sb, In) has been prepared by melting the metal chloride, iodide or acetate with 1,2-dicyanobenzene in the presence of potassium methylate. Crystallisation with tetra(n-butyl)ammonium bromide or hydroxide (( n Bu 4 N)Br/OH), tetra(n-pentyl)ammonium chloride (( n Pe 4 N)Cl) or bis(triphenylphosphine)iminium halide ((PNP)X; X = Br, I) yields the corresponding red-purple complex salt ( n Bu 4 N)[M(pc 2± ) 2 ] (M = Bi (1), La (3), Ce (2)), ( n Bu 4 N)[M(pc 2± ) 2 ]´x CH 3 OH (M = Bi (5), Pr (6), Sm (7); 0 9 x 9 1), ( n Pe 4 N)[La(pc 2± ) 2 ] (4), ( n Bu 4 N)[Pr(pc 2± ) 2 ]´2 py (10), ( n Bu 4 N)[Sb(pc 2± ) 2 ]´2 thf (11), (PNP) 2 [M(pc 2± ) 2 ]Br2 Et 2 O (M = Sb (12), Bi (13)), and (PNP) 2 [In(pc 2± ) 2 ]I´2 Et 2 O (14). Bronze coloured diphthalocyaninato(1±)metal(III) polyiodide, [M(pc ± ) 2 ]I 2 (M = Sc, Y) has been prepared similarly in the presence of ammonium iodide. Reduction with ( n Bu 4 N)OH provides ( n Bu 4 N)[M(pc 2± ) 2 ]´x CH 3 OH (M = Y (8), Sc (9); 0 9 x 9 1). Spectral properties (UV/VIS/NIR; IR; resonance Raman) of diphthalocyaninates in their different ring oxidation states (2±/2±; 2±/1±; 1±/1±) are discussed. 1±3 crystallise in the tetragonal (P4/ncc), 5±9 in the orthorhombic (Pna2 1 ), 10, 11 in the triclinic (P-1), and 4, 12± 14 in the monoclinic crystal system (4: P2 1 /m; 12: C2/c; 13, 14: P2/c). Ecliptic rotamers with skew angles ranging from 4.1°to 6.0°are found in 1±3, and staggered rotamers with skew angles ranging from 35.8°to 45.0°are found in 4±14. The mean M±N i bond lengths and interplanar distances increase monotonically with the ionic radius of the metal ion. Both distances deviate notably from this linear correlation in the Sb III and Bi III derivatives. The discrepancy is presumably due to the sterical dominance of the ns 2 lone-pair character. The actual size of eight co-ordinated Sb III and Bi III is estimated to be R 8 » 1.02(Sb)/1.11(Bi) A Ê . In every complex salt, the pc ligand is severely distorted from planarity and can adopt domed, saddled, waved and mixed non-planar conformations; the crystal symmetry is the most important factor for the conformational heterogeneity.

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Magnetic susceptibility, heat capacity, and optical conductivity of LiPc and LiPcI

Cited by 18 publications

References 2 publications

Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO 3

Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO 3

Calorimetric Investigation of Phase Transitions Occurring in Molecule-Based Magnets

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