Parasitic phases at the origin of magnetic moment in BiFeO3 thin films grown by low deposition rate RF sputtering

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQA series of epitaxial BiFeO3 thin films has been grown under high partial pressure in a pure O-2 atmosphere, which leads to a low deposition rate. The samples grown under these conditions have presented an evolution of the quality of the epitaxy as the deposition temperature increases, however, spurious beta-Bi2O3 and supertetragonal BiFeO3 phases are present in the films grown at higher temperatures. The presence of gamma-Fe2O3 is reported in one growing condition, and has been attributed to the origin of hysteretic ferromagnetic behavior. A second kind of magnetism, with higher magnetic moment and anhysteretic behaviour, is attributed to the presence of mixed phases of BiFeO3.1221215FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ2012/18397-12012/51198-2309354/2015-3This work was supported by FAPESP (Project No. 2012/51198-2). Some of the XRD measurements were performed at the XRD2 beamline of the LNLS/CNPEM under Project Nos. 20150162 and 20160908. The authors thank the LNNano/CNPEM for XRD/XRR, AFM and sputtering facilities, the LIEC/UFSCar for the SQUID measurements, and M. M. Soares for important discussions regarding the structural characterization. P.S. thanks FAPESP for financial support (Project No. 2012/18397-1). J.C.C. acknowledges support from CNPq (Project No. 309354/2015-3)

Conservation of Nickel Ion Single-Active Site Character in a Bottom-Up Constructed π-Conjugated Molecular Network

On-surface chemistry holds the potential for ultimate miniaturization of functional devices. Porphyrins are promising building-blocks in exploring advanced nanoarchitecture concepts. More stable molecular materials of practical interest with improved charge transfer properties can be achieved by covalently interconnecting molecular units. On-surface synthesis allows to construct extended covalent nanostructures at interfaces not conventionally available. Here, we address the synthesis and properties of covalent molecular network composed of interconnected constituents derived from halogenated nickel tetraphenylporphyrin on Au(111). We report that the π-extended two-dimensional material exhibits dispersive electronic features. Concomitantly, the functional Ni cores retain the same single-active site character of their single-molecule counterparts. This opens new pathways when exploiting the high robustness of transition metal cores provided by bottom-up constructed covalent nanomeshes

Características de carcaça e do couro de bovinos precoces e superprecoces.

Objetivou-se avaliar o efeito do sistema de produção sobre características produtivas e do couro de bovinos cruzados precoces e superprecoces. Foram utilizados 36 animais, sendo 16 provenientes do sistema superprecoce (10 machos castrados e seis fêmeas), terminados em confinamento e 20 animais do sistema precoce (10 machos castrados e 10 fêmeas), terminados em pastagens, recebendo suplementação protéico energética (1 kg/dia/animal). Após o abate os couros foram processados até a etapa de couro semi-acabado, onde foram retiradas as amostras da região do dorsolombar para os ensaios físico-mecânicos de tração e rasgamento. Houve efeito do sistema de produção para ganho de peso total (GPT), ganho médio diário (GMD), área de olho de lombo (AOL), espessura de gordura subcutânea (EGS), marmoreio, peso da pele ao abate (PPe1) e perdas com a padronização, com menores médias para animais precoces. As perdas apresentadas pelas fêmeas foram 14,48 e 6,88 kg, e para os machos castrados 9,32 e 4,84 kg, respectivamente para superprecoces e precoces. As médias de PA, peso da pele padronizada e área do couro Wet-blue dos machos castrados foram 473,60 kg, 40,60 kg e 4,52 m², respectivamente, para superprecoces e 462,83 kg, 29,77 kg e 4,31 m², respectivamente, para precoces. Não houve efeito de sexo e de sistema de produção para as características avaliadas nos ensaios físicos mecânicos no couro de bovinos precoces e superprecoces

Thermal nonequilibrium and viscous dissipation in the thermal entrance region of a Darcy flow with streamwise periodic boundary conditions

The thermal entrance region in a plane-parallel channel filled by a fluid saturated porous medium is investigated with reference to steady forced convection and to a thermal boundary condition given by a wall temperature longitudinally varying with a sinusoidal law. The effect of viscous dissipation in the fluid is taken into account, and a two-temperature model is employed in order to evaluate separately the local fluid and solid matrix temperatures. The asymptotic temperature distributions are determined analytically. The governing equations in the thermal entrance region are solved numerically by a finite element method and by the method of lines. \ua9 2011 American Society of Mechanical Engineers