We report on synthesis and general physical properties of the solid solutions Nd1-xLnxNiO3; Ln = ... more We report on synthesis and general physical properties of the solid solutions Nd1-xLnxNiO3; Ln = Sm, Eu, Gd, Er, Yb; 0 ≤ x ≤ 1. The samples were prepared through sol-gel precursors and were subjected to heat treatments at temperatures T ≤ 1000°C under oxygen pressures as high as 70 atm. From the results of x-ray powder diffraction we have
We performed measurements of magnetic susceptibility, electrical resistivity, and magnetoresistan... more We performed measurements of magnetic susceptibility, electrical resistivity, and magnetoresistance in magnetic fields of up to 18 T in the magnetic superconductor RuGd1.4Ce0.6Sr2Cu2O10- delta synthesized in oxygen pressures up to 95 atm. The magnetic-susceptibility data show the occurrence of an antiferromagnetic state below TN~175 K, followed by the development of a weak ferromagnetic state near TM~100 K, and followed further
The technological interest in transparent conductive oxide films (TCOs) has motivated several wor... more The technological interest in transparent conductive oxide films (TCOs) has motivated several works in processing techniques, in order to obtain adequate routes to application. In this way, this work describes a new route to obtain antimony-doped tin oxide (ATO) films, based in colloidal dispersions of oxide nanocrystals. The nanoparticles were obtained by a hydrolisis method, using SnCl2 and SbCl3 in ethanolic solutions. The residual halides were removed by dyalisis, obtaining a limpid and transparent colloidal suspension. By this, the method offers the advantage of producing ultrathin films without organic contaminants. This route was employed to produce films with 5, 10, 14, and 18 mol% Sb doping, with thickness ranging from 40 to 70 nm. The physical characterization of the samples showed a uniform layer deposition, resulting in good packing density and high transmittance. A preliminar electrical study confirmed the low electrical resistivity even in the ultrathin films, in such level similar of reported data. The method described is similar in some aspects to layer-by-layer (LbL) techniques, allowing fine control of thickness and interesting properties for ultrathin films, however, with low cost when compared to similar routes.
We report on the synthesis of two and three dimensional carbonaceous sponges produced directly fr... more We report on the synthesis of two and three dimensional carbonaceous sponges produced directly from graphene oxide (GO) into which functionalized iron nanoparticles can be introduced to render it magnetic. This simple, low cost procedure, wherein an iron polymeric resin precursor is introduced into the carbon framework, results in carbon-based materials with specific surface areas of the order of 93 and 66 m(2) g(-1), compared to approx. 4 m(2) g(-1) for graphite, decorated with ferromagnetic iron nanoparticles giving coercivity fields postulated to be 216 and 98 Oe, values typical for ferrite magnets, for 3.2 and 13.5 wt% Fe respectively. The strongly magnetic iron nanoparticles are robustly anchored to the GO sheets by a layer of residual graphite, on the order of 5 nm, formed during the pyrolysis of the precursor material. The applicability of the carbon sponges is demonstrated in their ability to absorb, store and subsequently elute an organic dye, Rhodamine B, from water as req...
We report on synthesis and general physical properties of the solid solutions Nd1-xLnxNiO3; Ln = ... more We report on synthesis and general physical properties of the solid solutions Nd1-xLnxNiO3; Ln = Sm, Eu, Gd, Er, Yb; 0 ≤ x ≤ 1. The samples were prepared through sol-gel precursors and were subjected to heat treatments at temperatures T ≤ 1000°C under oxygen pressures as high as 70 atm. From the results of x-ray powder diffraction we have
We performed measurements of magnetic susceptibility, electrical resistivity, and magnetoresistan... more We performed measurements of magnetic susceptibility, electrical resistivity, and magnetoresistance in magnetic fields of up to 18 T in the magnetic superconductor RuGd1.4Ce0.6Sr2Cu2O10- delta synthesized in oxygen pressures up to 95 atm. The magnetic-susceptibility data show the occurrence of an antiferromagnetic state below TN~175 K, followed by the development of a weak ferromagnetic state near TM~100 K, and followed further
The technological interest in transparent conductive oxide films (TCOs) has motivated several wor... more The technological interest in transparent conductive oxide films (TCOs) has motivated several works in processing techniques, in order to obtain adequate routes to application. In this way, this work describes a new route to obtain antimony-doped tin oxide (ATO) films, based in colloidal dispersions of oxide nanocrystals. The nanoparticles were obtained by a hydrolisis method, using SnCl2 and SbCl3 in ethanolic solutions. The residual halides were removed by dyalisis, obtaining a limpid and transparent colloidal suspension. By this, the method offers the advantage of producing ultrathin films without organic contaminants. This route was employed to produce films with 5, 10, 14, and 18 mol% Sb doping, with thickness ranging from 40 to 70 nm. The physical characterization of the samples showed a uniform layer deposition, resulting in good packing density and high transmittance. A preliminar electrical study confirmed the low electrical resistivity even in the ultrathin films, in such level similar of reported data. The method described is similar in some aspects to layer-by-layer (LbL) techniques, allowing fine control of thickness and interesting properties for ultrathin films, however, with low cost when compared to similar routes.
We report on the synthesis of two and three dimensional carbonaceous sponges produced directly fr... more We report on the synthesis of two and three dimensional carbonaceous sponges produced directly from graphene oxide (GO) into which functionalized iron nanoparticles can be introduced to render it magnetic. This simple, low cost procedure, wherein an iron polymeric resin precursor is introduced into the carbon framework, results in carbon-based materials with specific surface areas of the order of 93 and 66 m(2) g(-1), compared to approx. 4 m(2) g(-1) for graphite, decorated with ferromagnetic iron nanoparticles giving coercivity fields postulated to be 216 and 98 Oe, values typical for ferrite magnets, for 3.2 and 13.5 wt% Fe respectively. The strongly magnetic iron nanoparticles are robustly anchored to the GO sheets by a layer of residual graphite, on the order of 5 nm, formed during the pyrolysis of the precursor material. The applicability of the carbon sponges is demonstrated in their ability to absorb, store and subsequently elute an organic dye, Rhodamine B, from water as req...
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