Spin Injection as a Source of the Metamagnetic Phase Transition

2010 ◽  
Vol 168-169 ◽  
pp. 461-464
Author(s):  
A.A. Zyuzin ◽  
A.Y. Zyuzin
Keyword(s):  
Phase Transition ◽  
Current Flow ◽  
Spin Injection ◽  
Threshold Value ◽  
Order Type ◽  
Ferromagnetic Metal ◽  
Current Dependence ◽  
First Order ◽  
Magnetization State ◽  
State Region

We consider a metamagnetic phase transition of itinerant electrons in the metamagnetic- ferromagnetic metal junction. The current flow between a ferromagnetic metal and a metamagnetic metal produces the non-equilibrium spin imbalance acting as an effective magnetic field and initiating the first-order type transition from low- to high-magnetization states of the metamagnet in the vicinity of the ferromagnet. We show that the current dependence of the length of high-magnetization state region diverges at some threshold value, due to nonequilibrium shift, generated in a contact between the high and low magnetization states of the metamagnetic metal.

Molecular Dynamic Simulation of Zigzag Silicon Carbide Nanoribbon

2021 ◽  
Vol 32 ◽  
Author(s):  
Hang Thi Thuy Nguyen
Keyword(s):  
Phase Transition ◽  
Molecular Dynamics ◽  
Silicon Carbide ◽  
Md Simulation ◽  
Structural Evolution ◽  
Order Type ◽  
Distribution Functions ◽  
Heating Process ◽  
Initial Model ◽  
First Order

The heating process of zigzag silicon carbide nanoribbon (SiCNR) is studied via molecular dynamics (MD) simulation. The initial model contained 10000 atoms is heating from 50K to 6000K to study the structural evolution of zigzag SiCNR. The melting point is defined at 4010K, the phase transition from solid to liquid exhibits the first-order type. The mechanism of structural evolution upon heating is studied based on the radiral distribution functions, coordination number, ring distributions, and angle distributions.

SOFTENING OF PHASE TRANSITION BY RANDOM DISTRIBUTION OF BIMODAL-BONDS IN THE 2D 8-STATE POTTS MODEL

1999 ◽  
Vol 10 (05) ◽  
pp. 961-966
Author(s):  
FATIH YAŞAR ◽  
YIĞIT GÜNDÜÇ ◽  
TARIK ÇELIK
Keyword(s):  
Phase Transition ◽  
Potts Model ◽  
Random Distribution ◽  
Finite Size ◽  
Threshold Value ◽  
Two Dimensions ◽  
First Order ◽  
Size Dependent ◽  
First Order Phase Transition ◽  
First Order Phase

We investigated the influence of the distribution of bimodal bonds on phase transition in 8-state Potts model in two dimensions. We show that there is a finite size dependent threshold value of the introduced quenched randomness in the bond distribution for rounding the first-order phase transition.

STUDY OF AUTOCORRELATION TIMES IN 2D POTTS MODEL UNDER QUENCHED BOND RANDOMNESS

2000 ◽  
Vol 11 (04) ◽  
pp. 707-712
Author(s):  
FATIH YAŞAR ◽  
YIĞIT GÜNDÜÇ ◽  
TARÍK ÇELIK
Keyword(s):  
Phase Transition ◽  
Order Phase Transition ◽  
Potts Model ◽  
Cluster Algorithm ◽  
Threshold Value ◽  
Two Dimensions ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

The q = 8 state Potts model with varying amount of quenched bond randomness is simulated in two dimensions by using a cluster algorithm. It is shown that, by monitoring the autocorrelation times, one can trace down the threshold value of the introduced quenched bond randomness for the rounding of the first-order phase transition.

Isolated versus Condensed Anion Structure IV: An NQR Study and X-ray Structure Analysis of [H3N(CH2)3NH3]CdI4 * 2H2O, [H3CNH2(CH2)3NH3]CdBr4, [(CH3)4N]2CdBr 4, and [(CH3)3S]2CdBr4*

1998 ◽  
Vol 53 (8) ◽  
pp. 717-724 ◽  
Author(s):  
Hideta Ishiharaa ◽  
Keizo Horiuchib ◽  
Shi-qi Douc ◽  
Thorsten M. Gesingc ◽  
J.-Christian Buhlc ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase I ◽  
Phase Ii ◽  
Order Phase Transition ◽  
Transition Point ◽  
Order Type ◽  
First Order ◽  
Dsc Measurements ◽  
First Order Phase Transition ◽  
Transition Entropy

Abstract The phase I of [H3N(CH2)3NH3]CdI4 • 2H2O (1) crystallizes with isolated [CdI4]2-tetrahedra; monoclinic, C2/c, Z = 8, a = 1702.6(3), b= 1459.3(3), c= 1555.5(3) pm, and ß= 120.32(3)° at 299 K. (1) shows a first-order phase transition at T1↔II = 245 K. The eight 127I(v1) NQR lines in phase II change discontinuously into four lines in phase I. The transition entropy from DSC measurements, ∆S = 5.0 J K1- mol-1 , shows that this transition is probably due to order-disorder of cations. [H3CNH2(CH2)3NH3]CdBr4 (2) crystallizes with isolated [CdBr4]2- tetrahedra; orthorhombic P212121, Z = 4,a= 1447.8(5), b = 1280.3 (4), c = 709.7(3) pm at 299 K. (2) shows four 81Br NQR lines between II and around 325 K, above which temperature the lines disappear. [(CH3)4N]2CdBr4 (3) shows a second-order phase transition at T1↔II = 271 K. Three of four 81Br NQR lines in phase II disappear below this transition point, the other line can be observed up to 315 K. The transition entropy, ∆S = 9.01 J KT-1 mol-1 , indicates that the transition is an order-disorder type of the cations. [(CH3)3S]2CdBr4 (4) shows a first-order type phase transition at T1↔II = 304 K. The four lines spectrum of 81Br NQR is observed in phase II and disappears above the transition point. The transition entropy, ∆S = 46.8 J K- 1 mol-1 is abnormally large. The role of the hydrogen bond and the bridging power between the halogen and cadmium atoms upon the formation of the condensed anion structure is discussed.

Nonequilibrium first-order type phase transition in an electron-vibration system

1979 ◽  
Vol 74 (1-2) ◽  
pp. 36-38 ◽  
Author(s):  
I.Sh. Averbukh ◽  
V.A. Kovarsky ◽  
N.F. Perelman
Keyword(s):  
Phase Transition ◽  
Order Type ◽  
Vibration System ◽  
First Order ◽  
Type Phase

scholarly journals Electric properties of olive oil under pressure

2021 ◽  
Author(s):  
L. T. Pawlicki ◽  
R. M. Siegoczyński ◽  
S. Ptasznik ◽  
K. Marszałek
Keyword(s):  
Molecular Structure ◽  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Olive Oil ◽  
Material Parameters ◽  
First Order ◽  
Long Time ◽  
Capacitive Reactance ◽  
First Order Phase

AbstractThe main purpose of the experiment was a thermodynamic research with use of the electric methods chosen. The substance examined was olive oil. The paper presents the resistance, capacitive reactance, relative permittivity and resistivity of olive. Compression was applied with two mean velocities up to 450 MPa. The results were shown as functions of pressure and time and depicted on the impedance phase diagram. The three first order phase transitions have been detected. All the changes in material parameters were observed during phase transitions. The material parameters measured turned out to be the much more sensitive long-time phase transition factors than temperature. The values of material parameters and their dependence on pressure and time were compared with the molecular structure, arrangement of molecules and interactions between them. Knowledge about olive oil parameters change with pressure and its phase transitions is very important for olive oil production and conservation.

scholarly journals Elastic Properties and Energy Loss Related to the Disorder–Order Ferroelectric Transitions in Multiferroic Metal–Organic Frameworks [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3]

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3125
Author(s):  
Zhiying Zhang ◽  
Hongliang Yu ◽  
Xin Shen ◽  
Lei Sun ◽  
Shumin Yue ◽  
...  
Keyword(s):  
Phase Transition ◽  
Energy Loss ◽  
Elastic Properties ◽  
Ferroelectric Phase ◽  
Loss Modulus ◽  
Structural Phase ◽  
Metal Organic Frameworks ◽  
First Order ◽  
Metal Organic ◽  
Elastic Anomalies

Elastic properties are important mechanical properties which are dependent on the structure, and the coupling of ferroelasticity with ferroelectricity and ferromagnetism is vital for the development of multiferroic metal–organic frameworks (MOFs). The elastic properties and energy loss related to the disorder–order ferroelectric transition in [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3] were investigated using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The DSC curves of [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3] exhibited anomalies near 256 K and 264 K, respectively. The DMA results illustrated the minimum in the storage modulus and normalized storage modulus, and the maximum in the loss modulus, normalized loss modulus and loss factor near the ferroelectric transition temperatures of 256 K and 264 K, respectively. Much narrower peaks of loss modulus, normalized loss modulus and loss factor were observed in [(CH3)2NH2][Mg(HCOO)3] with the peak temperature independent of frequency, and the peak height was smaller at a higher frequency, indicating the features of first-order transition. Elastic anomalies and energy loss in [NH4][Mg(HCOO)3] near 256 K are due to the second-order paraelectric to ferroelectric phase transition triggered by the disorder–order transition of the ammonium cations and their displacement within the framework channels, accompanied by the structural phase transition from the non-polar hexagonal P6322 to polar hexagonal P63. Elastic anomalies and energy loss in [(CH3)2NH2][Mg(HCOO)3] near 264 K are due to the first-order paraelectric to ferroelectric phase transitions triggered by the disorder–order transitions of alkylammonium cations located in the framework cavities, accompanied by the structural phase transition from rhombohedral R3¯c to monoclinic Cc. The elastic anomalies in [NH4][Mg(HCOO)3] and [(CH3)2NH2][Mg(HCOO)3] showed strong coupling of ferroelasticity with ferroelectricity.

scholarly journals Gravitational wave signals of dark matter freeze-out

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Danny Marfatia ◽  
Po-Yan Tseng
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
First Order ◽  
Stochastic Background ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
First Order Phase ◽  
Freeze Out

Abstract We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future interferometers.

scholarly journals Dark Matter production from relativistic bubble walls

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Aleksandr Azatov ◽  
Miguel Vanvlasselaer ◽  
Wen Yin
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Electroweak Phase Transition ◽  
First Order ◽  
Matter Production ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
Higgs Portal ◽  
First Order Phase ◽  
Gravitational Background

Abstract In this paper we present a novel mechanism for producing the observed Dark Matter (DM) relic abundance during the First Order Phase Transition (FOPT) in the early universe. We show that the bubble expansion with ultra-relativistic velocities can lead to the abundance of DM particles with masses much larger than the scale of the transition. We study this non-thermal production mechanism in the context of a generic phase transition and the electroweak phase transition. The application of the mechanism to the Higgs portal DM as well as the signal in the Stochastic Gravitational Background are discussed.

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