Variabilidade temporal e intraespecífica dos constituintes voláteis das folhas de Lychnophora ericoides Mart.

Pavarini, Daniel Petinatti

doi:10.11606/d.60.2011.tde-28032012-155624

Cited by 5 publications

(5 citation statements)

References 14 publications

(14 reference statements)

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“…the antisymmetric state has lower energy. The above result also holds for body-centered tetragonal materials, with the modified tunneling matrix element [14]. Moreover, we see why the coupling between bilayers is so small: the tunneling matrix elements between bilayers are much smaller than those within a bilayer because c = 11.82Å ≫ d = 3.25Å.…”

supporting

confidence: 61%

NEUTRON SCATTERING SIGNATURE OF d-DENSITY WAVE ORDER IN THE CUPRATES

Chakravarty

Kee

Nayak

2001

Int. J. Mod. Phys. B

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An ordered d-density wave (DDW) state has been proposed as an explanation of the pseudogap phase in underdoped high-temperature superconductors. The staggered currents associated with this order have signatures which are qualitatively different from those of ordered spins. We apply the order parameter theory to an orthorhombic bilayer system and show that the expected magnitude as well as the momentum, energy, and polarization dependence of the consequent neutron scattering is consistent with the findings of a recent experiment.

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supporting

confidence: 61%

NEUTRON SCATTERING SIGNATURE OF d-DENSITY WAVE ORDER IN THE CUPRATES

Chakravarty

Kee

Nayak

2001

Int. J. Mod. Phys. B

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“…The saturation magnetic field value, as extracted from the specific heat and ac susceptibility data, deviates significantly from the one predicted for an isotropic square lattice, and this result is conjectured to be a consequence of the frustrating magnetic interactions, in the bc layer, that have have been confirmed recently by quantum mechanical calculations. 33 Finally, it is noteworthy that a T 2 dependence of the specific heat has been reported for several frustrated 2D systems in zero magnetic field and was ascribed to various scenarios. While only a weak field dependence of the low temperature specific heat has been observed in Kagomé 34 and triangular 35 compounds, the linear increase of the b coefficient, as observed in Cu(tn)Cl 2 , points to the fact that even an infinitesimal field is able to introduce the changes.…”

Section: Discussionmentioning

confidence: 85%

Interplay of frustration and magnetic field in the two-dimensional quantum antiferromagnetCu(tn)Cl2

et al. 2009

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Specific heat and ac magnetic susceptibility measurements, spanning low temperatures (T ≥ 40 mK) and high magnetic fields (B ≤ 14 T), have been performed on a two-dimensional (2D) antiferromagnet Cu(tn)Cl2 (tn = C3H10N2). The compound represents an S = 1/2 spatially anisotropic triangular magnet realized by a square lattice with nearest-neighbor (J/kB = 3 K), frustrating nextnearest-neighbor (0 < J ′ /J < 0.6), and interlayer (|J ′′ /J| ≈ 10 −3 ) interactions. The absence of long-range magnetic order down to T = 60 mK in B = 0 and the T 2 behavior of the specific heat for T ≤ 0.4 K and B ≥ 0 are considered evidence of high degree of 2D magnetic order. In fields lower than the saturation field, Bsat = 6.6 T, a specific heat anomaly, appearing near 0.8 K, is ascribed to bound vortex-antivortex pairs stabilized by the applied magnetic field. The resulting magnetic phase diagram is remarkably consistent with the one predicted for the ideal square lattice, except that Bsat is shifted to values lower than expected. Potential explanations for this observation, as well as the possibility of a Berezinski-Kosterlitz-Thouless (BKT) phase transition in a spatially anisotropic triangular magnet with the Néel ground state, are discussed. PACS numbers: 75.40.-s, 75.10.JmRecently, Cu(tn)Cl 2 has been identified as a potential model system for the realization of the spatially anisotropic triangular lattice from the collinear Néel phase (J ′ /J < 0.6). 15 For Cu(tn)Cl 2 studied in B = 0, no evidence for long-range magnetic order was observed down to 60 mK, and the data suggested intralayer inter-action strengths of J/k B = 3 K and 0 < J ′ /J < 0.6, while the interlayer coupling is |J ′′ /J| ≈ 10 −3 . These interactions are described by the Hamiltonianwhere i, j label intralayer spins and k labels the interlayer ones. J J a b c FIG. 1: Realization of Heisenberg model of a spatially anisotropic triangular lattice within a single bc layer in Cu(tn)Cl2. The layers are stacked along the a direction. The full circles denote Cu 2+ ions.

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“…For the closest members of Ruddlesden-Popper series according to their physical and structural properties, Ca 2 RuO 4 and Sr 3 Ru 2 O 7 , respectively, one ends up with the following ab-initio estimates J ϳ 50 meV, ⌬ tet ϳ 20 meV and ⌬ o ϳ 5 meV. 40,41 These values set the ratios ⌬ tet / J ϳ 0.4 and ⌬ o / J ϳ 0.1, whose orders of magnitude are compatible with our choices of analysis for the regions of phase diagrams where major changes occur.…”

Section: Discussionmentioning

confidence: 99%

Field-induced orbital patterns in ferromagnetic layered ruthenates

2010

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We study the evolution of orbital patterns in ferromagnetic layered ruthenates due to the competition of Coulomb interactions, compressive c axis and orthorhombic distortions in the presence of a polarizing orbital field coupled to the angular momentum. By means of the exact diagonalization on a 2 ϫ 2 cluster and a cluster embedded analysis where interplaquette interaction is treated on mean-field level, we determine the groundstate phase diagram. Specifically, we demonstrate that, via the activation of two or three of t 2g local orbital configurations, an external field applied along different symmetry directions can lead to inequivalent orbital correlated states. Starting from an antiferro-orbital pattern, for the easy axis case an orbital ordered phase is induced, having strong next-nearest-neighbors ferro-orbital correlations. Otherwise, a field applied along the hard axis leads a reduction in local orbital moment in a way to suppress the orbital order.

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Variabilidade temporal e intraespecífica dos constituintes voláteis das folhas de Lychnophora ericoides Mart.

Abstract: PAVARINI, D.P. Timescale and intraspecifc variability of Lychnophora ericoides Mart. leave's volatile constituents. 2011. 126 p. Master'

Cited by 5 publications

References 14 publications

NEUTRON SCATTERING SIGNATURE OF d-DENSITY WAVE ORDER IN THE CUPRATES

NEUTRON SCATTERING SIGNATURE OF d-DENSITY WAVE ORDER IN THE CUPRATES

Interplay of frustration and magnetic field in the two-dimensional quantum antiferromagnetCu(tn)Cl2

Field-induced orbital patterns in ferromagnetic layered ruthenates

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