A first order reversal curve investigation of pressure hysteresis in multiferroics spin transition compound

2008 ◽  
Vol 103 (7) ◽  
pp. 07B905 ◽  
Author(s):  
Radu Tanasa ◽  
Alexandru Stancu ◽  
Epiphane Codjovi ◽  
Jorge Linares ◽  
François Varret ◽  
...  
Keyword(s):  
Spin Transition ◽  
First Order

Pressure effect investigated with first-order reversal-curve method on the spin-transition compounds [FexZn1−x(btr)2(NCS)2] · H2O (x=0.6,1)

2011 ◽  
Vol 83 (22) ◽  
Author(s):  
Aurelian Rotaru ◽  
Jorge Linares ◽  
François Varret ◽  
Epiphane Codjovi ◽  
Ahmed Slimani ◽  
...  
Keyword(s):  
Pressure Effect ◽  
Spin Transition ◽  
First Order ◽  
Curve Method

First-order reversal curve analysis of spin-transition thermal hysteresis in terms of physical-parameter distributions and their correlations

2005 ◽  
Vol 71 (1) ◽  
Author(s):  
Radu Tanasa ◽  
Cristian Enachescu ◽  
Alexandru Stancu ◽  
Jorge Linares ◽  
Epiphane Codjovi ◽  
...  
Keyword(s):  
Physical Parameter ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Curve Analysis ◽  
First Order ◽  
Parameter Distributions

scholarly journals Magnetic Collapse and the Behavior of Transition Metal Oxides: FeO at High Pressures

1997 ◽  
Vol 499 ◽  
Author(s):  
R. E. Cohen ◽  
Y. Fei ◽  
R. Downs ◽  
I. I. Mazin ◽  
D. G. Isaak
Keyword(s):  
Transition Metal Oxides ◽  
High Pressures ◽  
Local Density ◽  
Hexagonal Phase ◽  
Spin Transition ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
First Order ◽  
First Order Transition ◽  
Linearized Augmented Plane Wave

ABSTRACTLinearized augmented plane wave (LAPW) results are presented for FeO at high pressures using the Generalized Gradient Approximation (GGA) to study the high-spin low-spin transition previously predicted by LAPW with the Local Density Approximation (LDA) and Linear Muffin Tin Orbital (LMTO-ASA) methods within the GGA. We find a first-order transition at a pressure of about 105 GPa for the cubic lattice, consistent with earlier LAPW results, but much lower than obtained with the LMTO. The results are generally consistent with recent Mössbauer experiments that show a transition at about 100 GPa. We also discuss the origin of the transition, and show that it is not due to electrostatic crystal-field effects, but is rather due to hybridization and band widening with pressure. Examination of experimental data and computations suggest that the high pressure hexagonal phase of FeO is likely a polytype between the B8 NiAs and anti-B8 AsNi structures. The former is predicted to be an antiferromagnetic metal, and the latter an antiferromagnetic insulator. Implications for geophysics are discussed.

scholarly journals Evidence of Photo-Thermal Effects on the First-Order Thermo-Induced Spin Transition of [{Fe(NCSe)(py)2}2(m-bpypz)] Spin-Crossover Material

2019 ◽  
Vol 5 (2) ◽  
pp. 21 ◽  
Author(s):  
Kamel Boukheddaden ◽  
Houcem Fourati ◽  
Yogendra Singh ◽  
Guillaume Chastanet
Keyword(s):  
Thermal Effects ◽  
Spin Crossover ◽  
Evolution Equations ◽  
Thermal Hysteresis ◽  
Magnetic Measurements ◽  
Equations Of Motion ◽  
Spin Transition ◽  
Thermal Bath ◽  
Trapping Region ◽  
First Order

We have investigated by means of optical microscopy and magnetic measurements the first-order thermal spin transition of the [{Fe(NCSe)(py)2}2(m-bpypz)] spin-crossover compound under various shining intensities, far from the light-induced spin-state trapping region. We found evidence of photo-heating effects on the thermally-induced hysteretic response of this spin-crossover material, thus causing the shift of the thermal hysteresis to lower temperature regions. The experimental results are discussed in terms of the apparent crystal temperature and are analyzed theoretically using two evolution equations of motion, written on the high-spin (HS) fraction and heat balance between the crystal and the thermal bath. A very good qualitative agreement was found between experiment and theory in the stationary regime, explaining the experimental observations well and identifying the key factors governing these photo-thermal effects.

scholarly journals Neutron powder diffraction studies of two spin transition FeIIcomplexes under pressure

2008 ◽  
Vol 41 (3) ◽  
pp. 637-640 ◽  
Author(s):  
Vincent Legrand ◽  
Frédéric Le Gac ◽  
Philippe Guionneau ◽  
Jean-François Létard
Keyword(s):  
Ambient Temperature ◽  
Powder Diffraction ◽  
Structural Transition ◽  
Spin Crossover ◽  
Spin Transition ◽  
Neutron Powder Diffraction ◽  
Continuous Transition ◽  
First Order ◽  
New Type ◽  
Symmetry Change

The pressure dependences of the lattice parameters of two spin transition compounds have been derived from neutron powder diffraction measurements at ambient temperature. The study of Fe(PM–AzA)2(NCS)2[PM isN-2′-pyridylmethylene and AzA is 4-(phenylazo)aniline] has been used to validate this new type of investigation of spin crossover compounds, and the study of Fe(PM–BiA)2(NCS)2(BiA is 4-aminobiphenyl) has allowed the atypical spin crossover behaviour of this compound under pressure to be explained. In addition, this complex exhibits a pressure-induced structural transition with an associated symmetry change, inducing the transformation of Fe(PM–BiA)2(NCS)2into a different polymorph that avoids a first-order spin transition in favour of continuous transition.

Hysteretic behavior of Fe(phen)2(NCS)2 spin-transition microparticles vs. the environment: A huge reversible component resolved by first order reversal curves

2014 ◽  
Vol 104 (3) ◽  
pp. 031909 ◽  
Author(s):  
Radu Tanasa ◽  
Jérôme Laisney ◽  
Alexandru Stancu ◽  
Marie-Laure Boillot ◽  
Cristian Enachescu
Keyword(s):  
Spin Transition ◽  
Hysteretic Behavior ◽  
First Order ◽  
Reversible Component

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

Stochasting modeling of planetary ring systems

1984 ◽  
Vol 75 ◽  
pp. 461-469 ◽  
Author(s):  
Robert W. Hart
Keyword(s):  
Maximum Entropy ◽  
Ring System ◽  
The Sun ◽  
Ultimate State ◽  
Interparticle Interactions ◽  
Ring Systems ◽  
First Order ◽  
Planetary Ring ◽  
Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

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