92 research outputs found
Scanning probe imaging of coexistent ferromagnetism and ferroelectricity at room temperature
Room temperature coexistence of ferromagnetism and ferroelectricity in a thin
film of a novel material of nominal composition PbTi0.5Fe0.5O3-d is probed by
standard ferroelectric and ferromagnetic hysteresis loop measurements and by
scanning probe microscopy of various kinds. Both magnetic domains and
ferroelectric domains are observed in the same spatial region of the material,
implying phase coexistence in this system. For both order parameters, sample
morphology strongly affects roughness of the domain walls.Comment: 15 pages, 5 figure
Magneto-Seebeck effect in spin-valve with in-plane thermal gradient
We present measurements of magneto-Seebeck effect on a spin valve with
in-plane thermal gradient. We measured open circuit voltage and short circuit
current by applying a temperature gradient across a spin valve stack, where one
of the ferromagnetic layers is pinned. We found a clear hysteresis in these two
quantities as a function of magnetic field. From these measurements, the
magneto-Seebeck effect was found to be 0.82%.Comment: 10 Pages, 7 figure
Magnetoelectricity at room temperature in Bi0.9-xTbxLa0.1FeO3 system
Magnetoelectric compounds with the general formula, Bi0.9-xRxLa0.1FeO3 (R
=Gd, Tb, Dy, etc.), have been synthesized. These show the coexistence of
ferroelectricity and magnetism, possess high dielectric constant and exhibit
magnetoelectric coupling at room temperature. Such materials may be of great
significance in basic as well as applied research.Comment: 11 pages of text and figure
Efficiency of Pd impregnated sol-gel derived γ-alumina porous spheres as catalyst
Porous γ-alumina spheres having surface area as large as 300 m/gm are obtained
by using sol-gel process. γ-alumina supported Pd catalyst is synthesized by soaking it in
PdCl solution followed by drying and heating at 300 C/1 hr in hydrogen atmosphere.
Specific Surface Area of Pd coated alumina remained unaltered. The scanning electron microscopy
revealed uniform coating of Pd metal on the surface. The equivalent spherical diameter (ESD) of the
coated Pd metal particles is estimated to be 50. The catalytic efficiency is evaluated by
H-O combination reaction. The performance of this supported catalyst is found to be much
superior in comparison with Pd catalyst realized on commercially available alumina having surface area of
80 m/gm. The improved efficiency of the catalyst could be co-related to enhanced surface of
nano-structured Pd available for catalytic action. The added advantage of spherical shape of the support
material appeared in uniform and homogeneous loading of the catalyst bed. The results highlight the
important role played by support material in these type of catalysts
Synthesis of YBa<SUB>2</SUB>Cu<SUB>4</SUB>O<SUB>8</SUB> in air through complex precursor formation and fine-particle techniques
We report the successful synthesis in air of the superconductor YBa<SUB>2</SUB>Cu<SUB>4</SUB>O<SUB>8</SUB> (1-2-4) without the need of high oxygen pressure or an alkali-carbonate based catalyst. The technique involves formation, in solution, of a fine-particle-complex based precursor. The 1-2-4 phase then forms in air with a single firing of 30 min at 900°C and a T<SUB>c</SUB> near 80 K. We also report some results of attempts to prepare 1-2-4 using precursors from sol-gel and spray drying
Sol-gel: a novel method to synthesize YBa<SUB>2</SUB>Cu<SUB>4</SUB>O<SUB>8</SUB>
We report here the successful synthesis of the superconductor YBa<SUB>2</SUB>Cu<SUB>4</SUB>O<SUB>8</SUB>(1-2-4) through a solution based "sol-gel" technique which vastly simplifies its preparation. Unlike the conventional route, this does not require a high oxygen pressure during synthesis and yields totally single phase material. The technique involves formation in solution, of a fine-particle complex based precursor. The 1-2-4 phase, with a T<SUB>c</SUB> of 80K, is found to form in flowing oxygen with a single firing of 30 minutes at 900°C
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