Magnetoelastic couplings in the distorted diamond-chain compound azurite

We present results of ultrasonic measurements on a single crystal of the distorted diamond-chain compound azurite Cu-3(CO3)(2)(OH)(2). Pronounced elastic anomalies are observed in the temperature dependence of the longitudinal elastic mode c(22) which can be assigned to the relevant magnetic interactions in the system and their couplings to the lattice degrees of freedom. From a semiquantitative analysis of the magnetic contribution to c(22) the magnetoelastic coupling G = partial derivative J(2)/partial derivative epsilon(b) can be estimated, where J(2) is the intradimer coupling constant and epsilon(b) the strain along the intrachain b axis. We find an exceptionally large coupling constant of | G| similar to 3650 K highlighting an extraordinarily strong sensitivity of J(2) against changes of the b-axis lattice parameter. These results are complemented by measurements of the hydrostatic pressure dependence of J2 by means of thermal expansion and magnetic susceptibility measurements performed both at ambient and finite hydrostatic pressure. We propose that a structural peculiarity of this compound, in which Cu2O6 dimer units are incorporated in an unusually stretched manner, is responsible for the anomalously large magnetoelastic coupling.

Structural, microstructural, optical and electrical properties of (Pb,Ba,Sr)TiO3 films growth on conductive LaNiO3-coated LaAO(3)(100) and Pt/Ti/SiO2/Si substrates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cobalt(III) complexes with thiosemicarbazones as potential anti-Mycobacterium tuberculosis agents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and antimycobacterial activity of new pyrazolate-bridged dinuclear complexes of the type [Pd(mu-L)(N-3)(PPh3)](2) (PPh3 = triphenylphosphine; L = pyrazolates)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hydroxyquinoline derived vanadium(IV and V) and copper(II) complexes as potential anti-tuberculosis and anti-tumor agents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis and biological evaluation of ternary silver compounds bearing N,N-chelating ligands and thiourea: X-ray structure of [{Ag(bpy) (mu-tu)}(2)](NO3)(2) (bpy=2,2 '-bipyridine; tu = thiourea)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

N-Methyl-2-(1-methyl-3-phenyl­prop-2-en-1-yl­idene)hydrazinecarbo­thio­amide

In the title compound, C12H15N3S, the mol­ecule deviates slightly from planarity, with a maximum deviation from the mean plane of the non-H atoms of 0.2756 (6) Å for the S atom and a torsion angle for the N-N-C-N fragment of -7.04 (16)°. In the crystal, mol­ecules are linked by N-H...S hydrogen-bond inter­actions, forming centrosymmetric dimers. Additionally, one weak intra­molecular N-H...N hydrogen-bond inter­action is observed. The crystal packing shows a herringbone arrangement viewed along the c axis.

Formation and evolution of TiO2 nanotubes in alkaline synthesis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis, structural characterization, luminescent properties and theoretical study of three novel lanthanide metal-organic frameworks of Ho(III), Gd(III) and Eu(III) with 2,5-thiophenedicarboxylate anion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In silico infrared and Raman spectroscopy under pressure: The case of CaSnO3 perovskite

The CaSnO3 perovskite is investigated under geochemical pressure, up to 25 GPa, by means of periodic ab initio calculations performed at B3LYP level with local Gaussian-type orbital basis sets. Structural, elastic, and spectroscopic (phonon wave-numbers, infrared and Raman intensities) properties are fully characterized and discussed. The evolution of the Raman spectrum of CaSnO3 under pressure is reported to remarkably agree with a recent experimental determination [J. Kung, Y. J. Lin, and C. M. Lin, J. Chem. Phys. 135, 224507 (2011)] as regards both wave-number shifts and intensity changes. All phonon modes are symmetry-labeled and bands assigned. The single-crystal total spectrum is symmetry-decomposed into the six directional spectra related to the components of the polarizability tensor. The infrared spectrum at increasing pressure is reported for the first time and its main features discussed. All calculations are performed using the CRYSTAL14 program, taking advantage of the new implementation of analytical infrared and Raman intensities for crystalline materials. (C) 2015 AIP Publishing LLC.

Non-centrosymmetric crystals of new N-benzylideneaniline derivatives as potential materials for non-linear optics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Metalosupramoléculas discretas e Metal Organic Frameworks (MOFs) baseados em íons lantanídeos: design, síntese, caracterização e propriedades

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Crescimento epitaxial e caracterização de filmes finos: óxidos condutores e ferroelétricos preparados por deposição de solução química

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Compostos de Pd(II) contendo ligantes N,S-doadores: síntese, caracterização e estudo da atividade citotóxica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Espectroscopia de impedância em Fe3O2BO3 e α-MnO2 dopado com cobre

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)