The effect of pressure on the thermal hysteresis of the first‐order spin transition in bis(1,10‐phenanthroline‐2‐carbaldehyde phenylhydrazone) iron (II) complexes

1985 ◽  
Vol 83 (6) ◽  
pp. 3055-3061 ◽  
Author(s):  
E. König ◽  
G. Ritter ◽  
J. Waigel ◽  
H. A. Goodwin
Keyword(s):  
Thermal Hysteresis ◽  
Spin Transition ◽  
Effect Of Pressure ◽  
First Order

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 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.

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

scholarly journals Reversibility of the Magnetocaloric Effect in the Bean-Rodbell Model

2021 ◽  
Vol 7 (5) ◽  
pp. 60
Author(s):  
Luis M. Moreno-Ramírez ◽  
Victorino Franco
Keyword(s):  
Magnetic Field ◽  
Thermal Hysteresis ◽  
Entropy Change ◽  
Second Order ◽  
Zero Field ◽  
First Order ◽  
Magnetic Field Change ◽  
Magnetocaloric Materials ◽  
Moderate Magnetic Field ◽  
The Magnetic Field

The applicability of magnetocaloric materials is limited by irreversibility. In this work, we evaluate the reversible magnetocaloric response associated with magnetoelastic transitions in the framework of the Bean-Rodbell model. This model allows the description of both second- and first-order magnetoelastic transitions by the modification of the η parameter (η<1 for second-order and η>1 for first-order ones). The response is quantified via the Temperature-averaged Entropy Change (TEC), which has been shown to be an easy and effective figure of merit for magnetocaloric materials. A strong magnetic field dependence of TEC is found for first-order transitions, having a significant increase when the magnetic field is large enough to overcome the thermal hysteresis of the material observed at zero field. This field value, as well as the magnetic field evolution of the transition temperature, strongly depend on the atomic magnetic moment of the material. For a moderate magnetic field change of 2 T, first-order transitions with η≈1.3−1.8 have better TEC than those corresponding to stronger first-order transitions and even second-order ones.

First-order reversal curves analysis of rate-dependent hysteresis: The example of light-induced thermal hysteresis in a spin-crossover solid

2005 ◽  
Vol 72 (5) ◽  
Author(s):  
Cristian Enachescu ◽  
Radu Tanasa ◽  
Alexandru Stancu ◽  
Francois Varret ◽  
Jorge Linares ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
First Order ◽  
Rate Dependent

FORC method applied to the thermal hysteresis of spin transition solids: first approach of static and kinetic properties

2004 ◽  
Vol 343 (1-4) ◽  
pp. 15-19 ◽  
Author(s):  
Cristian Enachescu ◽  
Radu Tanasa ◽  
Alexandru Stancu ◽  
Epiphane Codjovi ◽  
Jorge Linares ◽  
...  
Keyword(s):  
Thermal Hysteresis ◽  
Spin Transition ◽  
Kinetic Properties

Dynamical control of the spin transition inside the thermal hysteresis loop of a spin-crossover single crystal

2016 ◽  
Vol 486 ◽  
pp. 187-191 ◽  
Author(s):  
Kamel Boukheddaden ◽  
Mouhamadou Sy ◽  
Miguel Paez-Espejo ◽  
Ahmed Slimani ◽  
François Varret
Keyword(s):  
Single Crystal ◽  
Hysteresis Loop ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Thermal Hysteresis Loop ◽  
Dynamical Control

Hypersonic and Dielectric Studies of Relaxor Ferroelectric Single Crystal

1999 ◽  
Vol 604 ◽  
Author(s):  
Chi-Shun Tu ◽  
V.H. Schmiidt ◽  
C.-H. Yeh ◽  
L.-F. Chen ◽  
C.-L. Tsai
Keyword(s):  
Phase Transition ◽  
Dielectric Permittivity ◽  
Single Crystal ◽  
Thermal Hysteresis ◽  
Relaxor Ferroelectric ◽  
Dipolar Relaxation ◽  
First Order ◽  
Dielectric Data ◽  
Scattering Spectra ◽  
Ferroelectric Single Crystal

AbstractBoth the longitudinal (LA) Brillouin back-scattering spectra and dielectric permittivity along the [001] direction have been measured as a function of temperature for a relaxor ferroelectric single crystal (PbMg1/3Nb2/3O3)0.68(PbTiO3)0.32 (PMN-32%PT). A sharp ferroelectric phase transition (which is associated with a Landau-Khalatnikov-like phonon damping maximum) was observed near 445 K. As temperature increases, a diffuse phase transition was detected near 280 K. In addition, the nature of the thermal hysteresis for the dielectric permittivity confirms that these transitions (near 280 and 445 K for heating procedure) are diffuse first-order and first-order, It respectively. The dielectric data prove the existence of an electric dipolar relaxation process below 300 K.

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