Fabrication of Grain-Aligned Bulks and Thick Films of Misfit Layered Cobalt Oxides by a Magneto-Scientific Process

2005 ◽  
Vol 886 ◽  
Author(s):  
Shigeru Horii ◽  
Taichi Okamoto ◽  
Toshiaki Kumagai ◽  
Tetsuo Uchikoshi ◽  
Tohru S. Suzuki ◽  
...  
Keyword(s):  
Scientific Method ◽  
Easy Axis ◽  
Thick Films ◽  
Partial Substitution ◽  
Magnetic Alignment ◽  
Cobalt Oxides ◽  
High Deposition Rate ◽  
Alignment Method ◽  
Scientific Process ◽  
Axis Parallel

ABSTRACTWe report the preparation of grain-aligned [Ca2CoO3−δ]0.62CoO2 (Ca349) thick films and the conversion of the easy axis of magnetization from the a-axis to the c-axis. The thick films were fabricated by a simultaneous usage of electrophoretic deposition and magnetic alignment methods (MEPD) at high deposition rate with the order of 10 mm/min. Moreover, a multi-layered thick film of Al2O3/Ca349/Al2O3/Ca0.9La0.1MnO3/Al2O3 was also fabricated by the MEPD method by the optimization of condition of each suspension. The conversion of the easy axis was performed crystallochemically for a [Bi2Sr2O4]0.55CoO2 (BiSr222) compound with the easy axis parallel to the a-axis in order to fabricate c-axis grain-oriented bulks by the magnetic alignment method. The substitution of Ca for Sr in the [(Bi0.5Pb0.5)2Sr2O4] block layer induced the change of the easy axis into the c-axis direction, and the magnetic anisotropy was increased by the partial substitution of rare earth elements of Pr, Nd, Tb and Dy for Ca. Using a compound of [(Bi0.5Pb0.5)2(Ca0.8Pr0.2)2O4]0.55CoO2, we have successfully prepared the c-axis grain-aligned bulk by the magneto-scientific method. Our present results indicate that the magneto-scientific method is one of the useful and realistic processes for production of thermoelectric modules.

Large thermopower in metallic misfit cobalt oxides : improvement by cationic substitutions

2001 ◽  
Vol 691 ◽  
Author(s):  
S. Hébert ◽  
L. B. Wang ◽  
A. Maignan ◽  
D. Pelloquin ◽  
M. Hervieu ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Rock Salt ◽  
Figure Of Merit ◽  
Partial Substitution ◽  
Crystallographic Structure ◽  
Cobalt Oxides ◽  
New Family ◽  
Edge Shared Octahedra

ABSTRACTThe thermoelectric properties of misfit cobaltites have been investigated. Their crystallographic structure consists in the stacking of layers of tilted CoO6 edge-shared octahedra, separated by rock-salt type layers. The Tl based family was first investigated : it is shown that by increasing the Tl content, the resistivity ρ can be reduced while keeping a large thermopower S. Another way to improve the figure of merit Z=S2/(ρκ) is to partially substitute Bi for Tl to increase S and keep a small ρ. A new family of Pb-based misfits has also been investigated. Two different techniques have been attempted to decrease ρ and/or increase S in this family : the partial substitution of Cu for Co, and the partial substitution of Ca for Sr.

Structural and Magnetic Properties of Epitaxial Co-Au Superlattices

1989 ◽  
Vol 151 ◽  
Author(s):  
C. H. Lee ◽  
Hui He ◽  
F. Lamelas ◽  
W. Vavra ◽  
C. Uher ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Molecular Beam ◽  
Easy Axis ◽  
Constant Thickness ◽  
Substrate Plane ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Axis Parallel ◽  
Structural And Magnetic Properties

ABSTRACTWe describe measurements on the structural and magnetic properties of Co–Au superlattices grown on Ge–buffered (110) GaAs by molecular beam epitaxy. Samples have been prepared with Co layer thicknesses ranging from 5–40Å and Au spacer layers of constant thickness, ∼ 16Å. X–ray scattering and high-resolution transmission electron microscopy show that the hcp Co layers grow epitaxially with the (0001) axis parallel to (111)Au and with the in–plane Co[1120] axis parallel to GaAs[001]. SQUID magnetometer measurements reveal a crossover in the magnetic anisotropy of the as–grown samples such that the easy axis is perpendicular to the substrate plane when the Co layer thickness is less than ∼19Å.

Development of Thermoelectric Bi-Based Cobaltites with an Easy Axis of Magnetization Parallel to theC-Axis for Magnetic Alignment

2005 ◽  
Vol 44 (No. 40) ◽  
pp. L1263-L1266 ◽  
Author(s):  
Toshiaki Kumagai ◽  
Shigeru Horii ◽  
Tetsuo Uchikoshi ◽  
Tohru S. Suzuki ◽  
Yoshio Sakka ◽  
...  
Keyword(s):  
Easy Axis ◽  
Magnetic Alignment

Model-Based Science and the Ethics of Ongoing Treatment Negotiation

2014 ◽  
Author(s):  
Douglas W. Heinrichs
Keyword(s):  
Medical Ethics ◽  
Philosophy Of Science ◽  
Scientific Method ◽  
Autonomous Agents ◽  
Treatment Decisions ◽  
Optimal Treatment ◽  
Scientific Process ◽  
Model Based ◽  
Current Thinking ◽  
Evidence In Medicine

Current thinking in medical ethics posits that treatment decisions should result from negotiation between clinician and patient as autonomous agents. However the view of science that underlies most thinking about evidence in medicine encourages the belief that in principle optimal evi-dence-based judgment as to best treatments can be reached by the clinician apart from such ne-gotiation, reducing negotiation to a sham process. A model-based notion of science, derived from a naturalistic philosophy of science, argues that the process of predicting optimal treatment re-quires consideration of a patient’s goals, and thus requires ongoing negotiations with the patient. Hence values are integral to the scientific process, not something extra-scientific that must be reconciled with it. From this perspective the clinician’s activity becomes one with scientific method rather than an ill-defined, and typically undervalued, art.

Nd–Fe–B thick films prepared at the high deposition rate of 90 µm/h

2007 ◽  
Vol 2 (4) ◽  
pp. 450-452
Author(s):  
Masaki Nakano ◽  
Hiroyuki Takeda ◽  
Fumitoshi Yamashita ◽  
Hirotoshi Fukunaga
Keyword(s):  
Deposition Rate ◽  
Thick Films ◽  
High Deposition Rate

STUDIES OF MAGNETIC PROPERTIES AND GHz PERMEABILITY OF PURE AMORPHOUS COBALT THIN FILMS

2008 ◽  
Vol 22 (07) ◽  
pp. 527-534 ◽  
Author(s):  
DONGMAO JIAO ◽  
JIANGONG LI ◽  
XUDONG ZHANG ◽  
SHU WANG
Keyword(s):  
Easy Axis ◽  
Magnetic Measurements ◽  
Uniaxial Anisotropy ◽  
Rf Sputtering ◽  
Amorphous Structure ◽  
Axis Parallel ◽  
Amorphous Structures ◽  
Cobalt Thin Films ◽  
5 Ghz ◽  
Deposited Films

Soft Co films deposited by a method which we called the "weak magnetron radio frequency (RF) sputtering" have amorphous structures. The amorphous structure varies with the increasing of P Ar . Static magnetic measurements show that all the films possess high saturation magnetization and a well-defined in-plane uniaxial anisotropy with the easy axis parallel with the applied field. The highest coercivity in the easy axis H ce and in the hard axis H ch is only 20 Oe and 9 Oe, respectively. The sputter pressure P Ar affects essentially the uniaxial anisotropy energy Ku. The GHz permeability of the as-deposited films was measured in the 0.1–5 GHz using the shorted microstrip transmission-line perturbation method. The full-width at half-maximum (FWHM) for the peak in the imaginary part of the permeability at resonance is about 1.3 GHz which is far broader than other FWHM reported.

BARIUM HEXAFERRITE THICK FILMS BY HOT PRESS SINTERING

2010 ◽  
Vol 24 (06) ◽  
pp. 561-566 ◽  
Author(s):  
H. C. JIANG ◽  
W. L. ZHANG ◽  
Y. HE ◽  
B. PENG ◽  
W. X. ZHANG
Keyword(s):  
Easy Axis ◽  
Thick Films ◽  
Barium Hexaferrite ◽  
Film Plane ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Remanence Ratio ◽  
Magnetic Easy Axis ◽  
Hot Press Sintering

BaFe 12 O 19 ferrite thick films were screen-printed and sintered at 1150°C under pressure (hot press sintering). The effects of the hot press sintering on the properties of barium hexaferrite thick films were investigated. The X-ray diffraction pattern shows improvement of the (00l) texture under pressure. The porosity size of the hot press sintering samples decreases obviously and the surface compactness is improved as the pressure is increased. The films are quite anisotropic with magnetic easy axis perpendicular to the film plane. The largest remanence ratio achieved is 0.75 under the highest pressure of 4 MPa.

The Benefits and Limits of the Scientific Method

2017 ◽  
pp. 255-269
Author(s):  
James Moffat
Keyword(s):  
Everyday Life ◽  
Scientific Method ◽  
Quantum Physics ◽  
Modern World ◽  
Partial Knowledge ◽  
Scientific Process ◽  
Human Race ◽  
Human Endeavor ◽  
Mathematical Equations

The underlying, and at first sight rather outrageous, hypothesis of science, is that there is order beneath the surface complexity of everyday life. In other words, there is an underlying simplicity which explains this complexity. Gaining even partial knowledge of this underlying simplicity has allowed us to produce all of the technology which sustains our modern world. But how did this all come about? The objective of this chapter is firstly to give you an understanding of the power of science. It represents about 2,000 years of human endeavor and is one of the greatest cultural achievements of the human race. Some of the current challenges to the scientific process and method, as we currently understand them, are then discussed, with illustrations drawn from advanced Quantum Physics. These are sketched out in plain English, without the use of mathematical equations.

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