1,462 research outputs found
Novel Coexistence of Superconductivity with Two Distinct Magnetic Orders
The heavy fermion Ce(Rh,Ir)In5 system exhibits properties that range from an
incommensurate antiferromagnet on the Rh-rich end to an exotic superconductor
on the Ir-rich end of the phase diagram. At intermediate composition where
antiferromagnetism coexists with superconductivity, two types of magnetic order
are observed: the incommensurate one of CeRhIn5 and a new, commensurate
antiferromagnetism that orders separately. The coexistence of f-electron
superconductivity with two distinct f-electron magnetic orders is unique among
unconventional superconductors, adding a new variety to the usual coexistence
found in magnetic superconductors.Comment: 3 figures, 4 page
Electrical and raman scattering studies of ZnO:P and ZnO:Sb thin films
A study on the structure, electrical and optical properties of ZnO thin films produced by r.f. magnetron sputtering and implanted either with phosphorous (P) or antimony (Sb) is reported in this work. Raman spectroscopy, X-ray diffraction, optical transmittance and Hall effect measurements have been employed to characterize the samples. X-ray diffraction and Raman scattering patterns confirm that, after a 500ºC annealing, the doped films keep a polycrystalline nature with (002) preferred orientation. These films are very transparent and Hall effect results show that all have p-type conduction, despite doping ion and dose. The electric resistivity reaches values of 0.012 (cm) and 0.042 (cm) for the P and Sb-doped samples, respectivel
Resposta do arroz de sequeiro à adubação nitrogenada e espaçamento.
O objetivo deste trabalho foi avaliar a interação entre diferentes doses de nitrogênio sobre a produtividade de arroz de sequeiro cultivado em diferentes espaçamentos
Pedogeochemical in alteration profiles in the region of Lavras, Minas Gerais. II- trace elements and rare earth elements
Na região de Lavras, MG, analisou-se o comportamento geoquímico dos elementos menores (EM) e elementos das terras raras (ETR) ao longo da evolução pedogenética em perfis de solos com horizonteB textural, individualizados a partir de rochas de composição ácida, intermediária e básica do substrato. Nos perfis, realizaram-se análises químicas de EM e ETR, avaliando perdas e ganhos pelo balanço químico de massa. O estudo possibilitou o grupamento dos EM em duas classes: (a)mobilidade moderada a alta: perda da rocha fresca até o sólum; (b)mobilidade moderada: enriquecimento relativo e eventualmente real no sólum. O comportamento dos ETR revelou grande mobilidade ao longo da evolução dos perfis de alteração.The geochemical behavior of trace elements (TE) and rare earth elements (REE) was evaluated in the region of Lavras (MG), during the pedogenetic evolution in soil profiles with argillic horizons differentiated by acid, intermediate and basic compositions of the parent material.Chemical analyses of TE and REE were performed along the profiles and gains and losses were evaluated through mass chemical balance.The study allowed to group the TE into two classes: (a)moderate to high mobility: loss from the consolidated rocks to the solum; and (b)moderate mobility: relative and occasionally real enrichments in the solum.The REE showed a great mobility throughout the evolution of the alteration profiles
Validating silicon polytrodes with paired juxtacellular recordings: method and dataset
Cross-validating new methods for recording neural activity is necessary to accurately interpret and compare the signals they measure. Here we describe a procedure for precisely aligning two probes for in vivo “paired-recordings” such that the spiking activity of a single neuron is monitored with both a dense extracellular silicon polytrode and a juxtacellular micropipette. Our new method allows for efficient, reliable, and automated guidance of both probes to the same neural structure with micrometer resolution. We also describe a new dataset of paired-recordings, which is available online. We propose that our novel targeting system, and ever expanding cross-validation dataset, will be vital to the development of new algorithms for automatically detecting/sorting single-units, characterizing new electrode materials/designs, and resolving nagging questions regarding the origin and nature of extracellular neural signals
Produtividade de arroz de terras altas com aplicação de micronutrientes no sulco de plantio.
O intuito deste experimento foi observar efeitos da aplicação em superfície do solo, dos micronutrientes Manganês (Mn), Boro (B), Zinco (Zn) e Cobre (Cu) na produtividade de arroz de terras altas em sistema semeadura direta
A versatile and compact capacitive dilatometer
We describe the design, construction, calibration, and operation of a
relatively simple differential capacitive dilatometer suitable for measurements
of thermal expansion and magnetostriction from 300 K to below 1 K with a
low-temperature resolution of about 0.05 angstroms. The design is characterized
by an open architecture permitting measurements on small samples with a variety
of shapes. Dilatometers of this design have operated successfully with a
commercial physical property measurement system, with several types of
cryogenic refrigeration systems, in vacuum, in helium exchange gas, and while
immersed in liquid helium (magnetostriction only) to temperatures of 30 mK and
in magnetic fields to 45 T.Comment: 8 pages, incorporating 6 figures, submitted to Rev. Sci. Instru
Efeito de regulador de crescimento e doses de nitrogênio na produtividade de arroz de terras altas.
O objetivo deste estudo foi verificar o efeito do regulador de crescimento em cultura de arroz de terras altas em sistema semeadura direta, em diferentes doses de nitrogênio aplicado em cobertura. O experimento foi conduzido na estação experimental da Embrapa Arroz e Feijão, em Santo Antônio de Goiás, GO, na safra 2011/2012
Heavy Fermion Behavior, Crystalline Electric Field Effects, and Weak Ferromagnetism in SmOs_{4}Sb_{12}
The filled skutterudite compound SmOs_{4}Sb_{12} was prepared in single
crystal form and characterized. The SmOs_{4}Sb_{12} crystals have the
LaFe_{4}P_{12}-type structure with lattice parameter a = 9.3085 Angstroms.
Specific heat measurements indicate a large electronic specific heat
coefficient of ~880 mJ/mol K^{2}, from which an enhanced effective mass m^{*} ~
170 m_{e} is estimated. The specific heat data also suggest crystalline
electric field (CEF) splitting of the Sm^{3+} J = 5/2 multiplet into a
Gamma_{7} doublet ground state and a Gamma_{8} quartet excited state separated
by 37 K. Electrical resistivity rho(T) measurements reveal a decrease in rho(T)
below ~50 K that is consistent with CEF splitting of ~33 K between a Gamma_(7)
doublet ground state and Gamma_{8} quartet excited state. Specific heat and
magnetic susceptibility measurements display a possible weak ferromagnetic
transition at ~2.6 K, which could be an intrinsic property of SmOs_4Sb_{12} or
possibly due to an unknown impurity phase.Comment: 24 pages, 11 Postscript figures, to be published in Physical Review
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