First- and second-order phase transitions in RE6Co2Ga (RE = Ho, Dy or Gd) cryogenic magnetocaloric materials

AbstractRare-earth (RE) rich intermetallics crystallizing in orthorhombic Ho6Co2Ga-type crystal structure exhibit peculiar magnetic properties that are not widely reported for their magnetic ordering, order of magnetic phase transition, and related magnetocaloric behavior. By tuning the type of RE element in RE6Co2Ga (RE = Ho, Dy or Gd) compounds, metamagnetic anti-to-paramagnetic (AF to PM) phase transitions could be tuned to ferro-to-paramagnetic (FM to PM) phase transitions. Furthermore, the FM ground state for Gd6Co2Ga is confirmed by density functional theory calculations in addition to experimental observations. The field dependence magnetocaloric and Banerjee’s criteria demonstrate that Ho6Co2Ga and Dy6Co2Ga undergo a first-order phase transition in addition to a second-order phase transition, whereas only the latter is observed for Gd6Co2Ga. The two extreme alloys of the series, Ho6Co2Ga and Gd6Co2Ga, show maximum isothermal entropy change (∣ΔS iso max (5 T)∣) of 10.1 and 9.1 J kg−1K−1 at 26 and 75 K, close to H2 and N2 liquefaction, respectively. This outstanding magnetocaloric effect performance makes the RE6Co2Ga series of potential for cryogenic magnetic refrigeration applications.

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The Effect of Fe Doping on the Magnetic and Magnetocaloric Properties of Mn5−xFexGe3

Advances in Materials Science and Engineering ◽

10.1155/2017/9854184 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Jeffrey Brock ◽

Nathanael Bell-Pactat ◽

Hong Cai ◽

Timothy Dennison ◽

Tucker Fox ◽

...

Keyword(s):

Phase Transition ◽

Order Phase Transition ◽

Room Temperature ◽

Entropy Change ◽

Second Order ◽

Ferromagnetic Transition ◽

Fe Doping ◽

First Order Phase Transition ◽

Magnetocaloric Properties ◽

First Order Phase

The magnetic and magnetocaloric properties of a series of minutely doped Mn5-xFexGe3 compounds that exhibit the D88-type hexagonal crystal structure at room temperature have been investigated. For all Fe concentrations, the alloys are ferromagnetic and undergo a second-order ferromagnetic-to-paramagnetic transition near room temperature. Although the small Fe doping had little effect on the ferromagnetic transition temperatures of the system, changes in the saturation magnetization and magnetic anisotropy were observed. For x≤0.15, all compounds exhibit nearly the same magnetic entropy change of ~7 J/kg K, for a field change of 50 kOe. However, the magnitude of the refrigerant capacities increased with Fe doping, with values up to 108.5 J/kg and 312 J/kg being observed for field changes of 20 kOe and 50 kOe, respectively. As second-order phase transition materials, the Mn5-xFexGe3 compounds are not subject to the various drawbacks associated with first-order phase transition materials yet exhibit favorable magnetocaloric effects.

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Effect of Alkyl Chain Length of Alcohols on Cholesteric Uniaxial to Cholesteric Biaxial Phase Transitions in a Potassium Laurate/Alcohol/Potassium Sulfate/Water/Brucine Lyotropic Mixture: Evidence of a First-Order Phase Transition

The Journal of Physical Chemistry B ◽

10.1021/jp310981d ◽

2013 ◽

Vol 117 (3) ◽

pp. 942-948 ◽

Cited By ~ 16

Author(s):

Dennys Reis ◽

Erol Akpinar ◽

Antônio Martins Figueiredo Neto

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Order Phase Transition ◽

Alkyl Chain ◽

Alkyl Chain Length ◽

Potassium Sulfate ◽

First Order ◽

Potassium Laurate ◽

First Order Phase Transition ◽

First Order Phase

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GRAVITATIONAL WAVES FROM COSMOLOGICAL PHASE TRANSITIONS

International Journal of Modern Physics A ◽

10.1142/s0217751x09044966 ◽

2009 ◽

Vol 24 (08n09) ◽

pp. 1541-1544

Author(s):

ARIEL MÉGEVAND

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Gravitational Waves ◽

Order Phase Transition ◽

Gravitational Radiation ◽

First Order ◽

First Order Phase Transition ◽

First Order Phase

I discuss the gravitational radiation produced in a first-order phase transition due to the turbulence that is caused by bubble expansion. I compare the cases of deflagration and detonation bubbles.

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Modeling of Phase Transitions Kinetics in Systems with Two Interacting Order Parameters

Materials Science Forum ◽

10.4028/www.scientific.net/msf.845.166 ◽

2016 ◽

Vol 845 ◽

pp. 166-169 ◽

Cited By ~ 1

Author(s):

Dmitry A. Kuzmin ◽

Igor V. Bychkov ◽

Ivan Yu. Biryukov ◽

Alexander P. Kamantsev ◽

Victor V. Koledov ◽

...

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Order Phase Transition ◽

Transition Process ◽

Order Parameters ◽

First Order ◽

First Order Phase Transition ◽

1D Model ◽

Coupled Solution ◽

First Order Phase

We present common 1D model of first order phase transition based on coupled solution of order parameters evolution and heat transfer equations. Such a model may be used for simulation of phase transitions in multiferroics or magnetostructural phase transitions, for example. First order phase transition process has been described by Landau-Khalatnikov-like equation with the thermodynamic potential of 2-3-4 and 2-4-6 types.

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Geometric Curvatures of Plane Symmetry Black Hole

Advances in High Energy Physics ◽

10.1155/2013/734138 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Shao-Wen Wei ◽

Yu-Xiao Liu ◽

Chun-E. Fu ◽

Hai-Tao Li

Keyword(s):

Phase Transition ◽

Black Hole ◽

Order Phase Transition ◽

Semiclassical Approximation ◽

Second Order ◽

Plane Symmetry ◽

First Order ◽

First Order Phase Transition ◽

Transition Points ◽

First Order Phase

We study the properties and thermodynamic stability of the plane symmetry black hole from the viewpoint of geometry. We find that the Weinhold curvature gives the first-order phase transition atN=1, whereNis a parameter of the plane symmetry black hole while the Ruppeiner one shows first-order phase transition points for arbitraryN≠1. Considering the Legendre invariant proposed by Quevedo et al., we obtain a unified geometry metric, which contains the information of the second-order phase transition. So, the first-order and second-order phase transitions can be both reproduced from the geometry curvatures. The geometry is also found to be curved, and the scalar curvature goes to negative infinity at the Davie phase transition points beyond semiclassical approximation.

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Specific heat and entropy change at the first order phase transition of La(Fe-Mn-Si)13-H compounds

Journal of Applied Physics ◽

10.1063/1.4928086 ◽

2015 ◽

Vol 118 (5) ◽

pp. 053907 ◽

Cited By ~ 42

Author(s):

Vittorio Basso ◽

Michaela Küpferling ◽

Carmen Curcio ◽

Cecilia Bennati ◽

Alexander Barzca ◽

...

Keyword(s):

Phase Transition ◽

Specific Heat ◽

Order Phase Transition ◽

Entropy Change ◽

First Order ◽

First Order Phase Transition ◽

First Order Phase

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Phase Transitions in 3D Site-Diluted Potts Model with Spin States q=4

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.168-169.357 ◽

2010 ◽

Vol 168-169 ◽

pp. 357-360 ◽

Cited By ~ 5

Author(s):

Akai K. Murtazaev ◽

A.B. Babaev ◽

G.Ya. Aznaurova

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Order Phase Transition ◽

Potts Model ◽

Finite Size ◽

Critical Parameters ◽

Spin States ◽

Spin Concentration ◽

First Order Phase Transition ◽

First Order Phase

We study the phase transitions and critical phenomena in 3D site-diluted (with nonmagnetic impurities) Potts model with spin states q=4 by Monte-Carlo method. The systems with linear sizes L=20-32 and spin concentrations p=1.00, 0.90, 0.65 are examined. Using the Binder cumulants method the forth order it is shown that the second-order phase transition is observed in strongly diluted model at spin concentration p=0.65; the pure model (p=1.00) and weakly diluted one (p=0.90) reveals the first-order phase transition. On the basis of finite-size scaling theory the static critical parameters of heat capacity, susceptibility, magnetization, and correlation length exponent are calculated.

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Phase transitions in neutron stars

International Journal of Modern Physics E ◽

10.1142/s0218301318300084 ◽

2018 ◽

Vol 27 (11) ◽

pp. 1830008 ◽

Cited By ~ 7

Author(s):

V. Dexheimer ◽

L. T. T. Soethe ◽

J. Roark ◽

R. O. Gomes ◽

S. O. Kepler ◽

...

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Equation Of State ◽

Neutron Stars ◽

Order Phase Transition ◽

Dense Matter ◽

First Order ◽

The Core ◽

First Order Phase Transition ◽

First Order Phase

In this paper, we review the most common descriptions for the first-order phase transition to deconfined quark matter in the core of neutron stars. We also present a new description of these phase transitions in the core of proto-neutron stars, in which more constraints are enforced so as to include trapped neutrinos. Finally, we calculate the emission of gravitational waves associated with deconfinement phase transitions, discuss the possibility of their detection, and how this would provide information about the equation of state of dense matter.

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Dark confinement and chiral phase transitions: gravitational waves vs matter representations

Journal of High Energy Physics ◽

10.1007/jhep01(2022)003 ◽

2022 ◽

Vol 2022 (1) ◽

Author(s):

Manuel Reichert ◽

Francesco Sannino ◽

Zhi-Wei Wang ◽

Chen Zhang

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Gravitational Wave ◽

Order Phase Transition ◽

Coupled Models ◽

Chiral Phase ◽

Strongly Coupled ◽

First Order ◽

First Order Phase Transition ◽

First Order Phase

Abstract We study the gravitational-wave signal stemming from strongly coupled models featuring both, dark chiral and confinement phase transitions. We therefore identify strongly coupled theories that can feature a first-order phase transition. Employing the Polyakov-Nambu-Jona-Lasinio model, we focus our attention on SU(3) Yang-Mills theories featuring fermions in fundamental, adjoint, and two-index symmetric representations. We discover that for the gravitational-wave signals analysis, there are significant differences between the various representations. Interestingly we also observe that the two-index symmetric representation leads to the strongest first-order phase transition and therefore to a higher chance of being detected by the Big Bang Observer experiment. Our study of the confinement and chiral phase transitions is further applicable to extensions of the Standard Model featuring composite dynamics.

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ON THE THEORY OF FIRST-ORDER PHASE TRANSITION IN ORDER-DISORDER FERROELECTRICS

International Journal of Modern Physics B ◽

10.1142/s0217979292000591 ◽

1992 ◽

Vol 06 (08) ◽

pp. 1181-1192 ◽

Cited By ~ 6

Author(s):

J.M. WESSELINOWA ◽

M.S. MARINOV

Keyword(s):

Phase Transition ◽

Phase Transitions ◽

Ising Model ◽

Order Phase Transition ◽

Transverse Field ◽

Spin Interaction ◽

Relative Polarization ◽

First Order ◽

First Order Phase Transition ◽

First Order Phase

Based on the Hamiltonian of the Ising model in a transverse field, we have considered the four-spin interaction which is responsible for the first-order phase transition observed in order-disorder ferroelectrics. Using the method of the retarded Green’s function we have determined the relative polarization, the spin-wave energy, the transverse and longitudinal damping. They are numerically calculated and discussed for different temperature and tunneling frequency values in the cases of first- and second-order phase transitions.

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