scholarly journals Ferromagnetic transition in Au- based Approximants

2014 ◽  
Vol 70 (a1) ◽  
pp. C90-C90
Author(s):  
Takanobu Hiroto ◽  
Kazuyasu Tokiwa ◽  
Taku Sato ◽  
Ryuji Tamura
Keyword(s):  
Magnetic Phase ◽  
Point Of View ◽  
Magnetic Phase Transitions ◽  
Experimental Point ◽  
Ferromagnetic Transition ◽  
Antiferromagnetic Phase ◽  
Space Filling ◽  
Icosahedral Cluster ◽  
The Difference ◽  
Related Compounds

The structure of Tsai-type magnetic quasicrystals and its related compounds (called approximants) are characterized by the space-filling of an icosahedral cluster which has a rare-earth icosahedron [1]. From an experimental point of view, such compounds have been known to show the spin glass like behavior without exception [2]. However, the discovery of the antiferromagnetic phase transition in the Cd-Tb approximant [3] gives a counterexample to this trend. Moreover, ferromagnetic transitions were observed in the Au-based approximant recently. In this paper, magnetic phase transitions in Au-Si-R (R= Gd ,Tb, Dy and Ho) approximants are discussed. In all the systems, the temperature dependence of magnetization show ferromagnetic transition at Tc. On the other hand, the magnetization curves below Tc are different between Gd-compound and non-Gd compounds. The difference in the magnetization may be attributed to the existence of the CEF effect in the non-Gd compounds which have non-zero orbital angular momentum.

STRUCTURAL AND MAGNETIC PHASE TRANSITIONS OF BiFeO3 INDUCED BY PRESSURE

2013 ◽  
Vol 06 (03) ◽  
pp. 1350026 ◽  
Author(s):  
HONG-JIAN FENG ◽  
XIAOYUN HU ◽  
HUIJUAN CHEN
Keyword(s):  
Phase Transitions ◽  
First Principles ◽  
Magnetic Phase ◽  
Structural Phase ◽  
Orthorhombic Phase ◽  
Magnetic Phase Transitions ◽  
Ferromagnetic Transition ◽  
First Principles Calculations ◽  
First Order ◽  
Pressure Region

First-principles calculations on BiFeO3 under low-pressure region show that the rhombohedral-monoclinic and rhombohedral-orthorhombic phase transitions can be found around the critical pressure value, ~9 GPa.We suggest that the structure involve the combination of these three phases and change to the pure orthorhombic phase gradually as pressure is beyond the critical value. Moreover, it is a first-order structural phase transition, accompanied with antiferromagnetic–ferromagnetic transition.

Strong Mn-Mn distance dependence of the Mn interlayer coupling inSmMn2Ge2-related compounds and its role in magnetic phase transitions

1994 ◽  
Vol 50 (22) ◽  
pp. 16410-16417 ◽  
Author(s):  
J. H. V. J. Brabers ◽  
A. J. Nolten ◽  
F. Kayzel ◽  
S. H. J. Lenczowski ◽  
K. H. J. Buschow ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Magnetic Phase ◽  
Interlayer Coupling ◽  
Magnetic Phase Transitions ◽  
Distance Dependence ◽  
Related Compounds

Clusterization Phenomena and Magnetic Phase Transitions in Rare Earth Intermetallics

2011 ◽  
Vol 170 ◽  
pp. 270-275 ◽  
Author(s):  
D.P. Rojas ◽  
N. Marcano ◽  
J.C. Gómez Sal
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Magnetic Phase ◽  
Ferromagnetic State ◽  
Magnetic Phase Transitions ◽  
Ferromagnetic Transition ◽  
Long Range Order ◽  
Percolation Process ◽  
Magnetic Cluster ◽  
First Order

Two cases of anomalous phase transitions in Ce intermetallics are presented. In CeIn2 multiple signatures of a first order paramagnetic-ferromagnetic transition at 22 K have been experimentally detected. We discuss possible mechanisms for such behaviour and the new studies in the La1-xCexIn2 series. In the he case of CeNi1-xCux the low temperature ferromagnetic long range order appears owing to a magnetic cluster percolation process, from a cluster glass state established above the ferromagnetic state.

scholarly journals Artificial Photosynthesis: Is Computation Ready for the Challenge Ahead?

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 299
Author(s):  
Silvio Osella
Keyword(s):  
Self Assembly ◽  
Artificial Photosynthesis ◽  
Light Harvesting ◽  
Point Of View ◽  
Experimental Point ◽  
Redox Active ◽  
Surface Assembly ◽  
Recent Developments ◽  
The Difference ◽  
Artificial Photosynthetic

A tremendous effort is currently devoted to the generation of novel hybrid materials with enhanced electronic properties for the creation of artificial photosynthetic systems. This compelling and challenging problem is well-defined from an experimental point of view, as the design of such materials relies on combining organic materials or metals with biological systems like light harvesting and redox-active proteins. Such hybrid systems can be used, e.g., as bio-sensors, bio-fuel cells, biohybrid photoelectrochemical cells, and nanostructured photoelectronic devices. Despite these efforts, the main bottleneck is the formation of efficient interfaces between the biological and the organic/metal counterparts for efficient electron transfer (ET). It is within this aspect that computation can make the difference and improve the current understanding of the mechanisms underneath the interface formation and the charge transfer efficiency. Yet, the systems considered (i.e., light harvesting protein, self-assembly monolayer and surface assembly) are more and more complex, reaching (and often passing) the limit of current computation power. In this review, recent developments in computational methods for studying complex interfaces for artificial photosynthesis will be provided and selected cases discussed, to assess the inherent ability of computation to leave a mark in this field of research.

scholarly journals Binary perovskite solid solutions and trends in their phase transitions temperatures variation

2021 ◽  
pp. 2160022
Author(s):  
G. A. Geguzina ◽  
I. G. Popova ◽  
A. E. Panich
Keyword(s):  
Phase Transitions ◽  
Solid Solutions ◽  
Magnetic Phase ◽  
Interatomic Bond ◽  
The Other ◽  
Magnetic Phase Transitions ◽  
Other Hand ◽  
The Difference ◽  
The One ◽  
The Way

Some of the known binary ABO3perovskites with ferro- (FE) or antiferroelectric (AFE) at [Formula: see text] and different magnetic phase transitions (PT): ferro-and antiferromagnetic at [Formula: see text] and also some of their solid solutions are considered. Some correlations between their FE or AFE and/or magnetic PTs temperatures, on the one hand, and their interatomic bond [Formula: see text]–O strains, on the other hand, have been constructed. It is shown that in the plotted diagrams these temperatures change with a change in [Formula: see text] values as follows: classical FEs are followed by multiferroics, starting with BiFeO3 and ending with YVO3, followed by classical AFEs. At the same time, the temperatures [Formula: see text] and [Formula: see text] experience maxima at the corresponding points for BiFeO3, then quickly decrease, and the difference between them, [Formula: see text]-[Formula: see text], basically also decreases, slightly increasing along the way to the point EuTiO3. which made it possible to systematize these [Formula: see text] and [Formula: see text].

A Theoretical Study on the Fundamental Chemical Reactions in Titanium Plasma-Enhanced CVD

1997 ◽  
Vol 490 ◽  
Author(s):  
K. Tsuda ◽  
K. Watanabe ◽  
Y. Ohshita ◽  
T. Takada
Keyword(s):  
Theoretical Study ◽  
Reaction Model ◽  
Point Of View ◽  
Experimental Point ◽  
Mo Calculations ◽  
Plasma Enhanced Cvd ◽  
Hartree Fock ◽  
Key Species ◽  
Stabilization Energies ◽  
The Difference

ABSTRACTThe important intermediates in the Ti plasma-enhanced CVD using TiCl4/Ar/H2 are investigated by ab initio molecular orbital (MO) calculations. From the experimental point of view, it is pointed out that'TiCls is a key species for the Ti deposition reaction. So, its reactivity with the Si and SiO2 substrates is estimated theoretically from the stabilization energy. The difference of the stabilization energies of TiCl3 between them, which is 12.3kcal/mol in Hartree-Fock level calculations with using the on-top deposition reaction model, indicates a longer existing time by the factor of 102 on SiO2 than on Si. In addition to these calculations, the stabilization energies on the suicide substrates are also calculated and compared with the results on the Si and Si02 substrates. But other reaction paths may have to be considered because the growth rates of Ti thin films onto between Si and SiO2 don't necessarily coincide with the tendency of calculated results.

Pleasure as a Sign of Efficacy of Mental Activity

1997 ◽  
Vol 2 (3) ◽  
pp. 226-234 ◽  
Author(s):  
Michel Cabanac ◽  
Chantal Pouliot ◽  
James Everett
Keyword(s):  
Evolutionary Psychology ◽  
Magnitude Estimation ◽  
Mental Activity ◽  
Point Of View ◽  
Macintosh Computer ◽  
Science Students ◽  
Cognitive Efficiency ◽  
Sensory Pleasure ◽  
The Difference ◽  
Mental Tasks

Previous work has shown that sensory pleasure is both the motor and the sign of optimal behaviors aimed at physiological ends. From an evolutionary psychology point of view it may be postulated that mental pleasure evolved from sensory pleasure. Accordingly, the present work tested empirically the hypothesis that pleasure signals efficacious mental activity. In Experiment 1, ten subjects played video-golf on a Macintosh computer. After each hole they were invited to rate their pleasure or displeasure on a magnitude estimation scale. Their ratings of pleasure correlated negatively with the difference par minus performance, i.e., the better the performance the greater the pleasure reported. In Experiments 2 and 3, the pleasure of reading poems was correlated with comprehension, both rated by two groups of subjects, science students and arts students. In the majority of science students pleasure was significantly correlated with comprehension. Only one arts student showed this relationship; this result suggests that the proposed relationship between pleasure and cognitive efficiency is not tautological. Globally, the results support the hypothesis that pleasure is aroused by the same mechanisms, and follows the same laws, in physiological and cognitive mental tasks and also leads to the optimization of performance.

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