scholarly journals Structure, Magnetocaloric Effect and Critical Behavior of the Fe60Co12Gd4Mo3B21 Amorphous Ribbons

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 34
Author(s):  
Agnieszka Łukiewska ◽  
Piotr Gębara
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Critical Behavior ◽  
Critical Exponents ◽  
Amorphous Structure ◽  
X Ray ◽  
Amorphous Ribbons ◽  
Spectroscopy Studies ◽  
Arrott Plots ◽  
Second Order Phase Transition

The aim of the paper was to study the structure, magnetic properties and critical behavior of the Fe60Co12Gd4Mo3B21 alloy. The X-ray diffractometry and the Mössbauer spectroscopy studies confirmed amorphous structure. The analysis of temperature evolution of the exponent n (ΔSM = C·(Bmax)n) and the Arrott plots showed the second order phase transition in investigated material. The analysis of critical behavior was carried out in order to reveal the critical exponents and precise TC value. The ascertained critical exponents were used to determine the theoretical value of the exponent n, which corresponded well with experimental results.

scholarly journals Determination of Phase Transition and Critical Behavior of the As-Cast GdGeSi-(X) Type Alloys (Where X = Ni, Nd and Pr)

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 185
Author(s):  
Piotr Gębara ◽  
Mariusz Hasiak
Keyword(s):  
Phase Transition ◽  
Order Phase Transition ◽  
Critical Behavior ◽  
Critical Exponents ◽  
Second Order ◽  
Experimental Result ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
Second Order Phase Transition

The aim of the paper is to present a study of the magnetocaloric effect and the nature of phase transition in the Gd80Ge15Si5 (S1), Gd75Ge15Si5Ni5 (S2), Gd75Ge15Si5Pr5 (S3) and Gd75Ge15Si5Nd5 (S4) alloys. The magnetic entropy changes determined for studied samples, under external magnetic field ~3T, were 11.91, 12.11, 5.08 and 4.71 J/(kg K) for S1, S2, S3 and S4, respectively. The values of refrigerant capacity (under ~3T) were 164, 140, 160 and 140 J/kg for S1, S2, S3 and S4, respectively. The first order phase transition was detected for samples S1 and S2, while specimens S3 and S4 manifested the second order phase transition at the Curie point (TC). The analysis of temperature evolution of the exponent n (ΔSM = C·(Bmax)n) showed the validity of this method in detecting either the first or the second order phase transition and the structural transition. The analysis of critical behavior was carried out for samples S3 and S4. The critical exponents and precise TC values were calculated. The ascertained critical exponents were used to determine the theoretical value of the exponent n, which corresponded well with experimental result.

Structure of ammonium hydrogen succinate above and below the phase transition around 170K

1996 ◽  
Vol 52 (2) ◽  
pp. 323-327 ◽  
Author(s):  
A. Hirano ◽  
Y. Kubozono ◽  
H. Maeda ◽  
H. Ishida ◽  
S. Kashino
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Hydrogen Bonds ◽  
Order Phase Transition ◽  
Space Group ◽  
X Ray ◽  
Ammonium Hydrogen ◽  
Significant Change ◽  
Short Hydrogen Bonds ◽  
Second Order Phase Transition

For crystals of ammonium hydrogen succinate it is known that the space group is P{\bar 1} with Z = 2 at 293 K and the second-order phase transition occurs around 170 K. X-ray crystal structure analyses above and below 170 K have been carried out in order to study the change in mode of short hydrogen bonds between the hydrogen succinate ions. The space group was determined to be P{\bar 1} at 150 and 190 K by structure analysis. No ordering of the H-atom positions in the short hydrogen bonds occurs by the phase transition. The hydrogen bonds show a decrease in the O...O distances with a decrease in temperature from 290 to 190 K, but no significant change in the geometries between 190 and 150 K. Disorder of the NH4 + ion is not observed at 297, 190 and 150 K. Significant change through the phase transition is found only in the geometry of one of the N—H...O hydrogen bonds between ammonium and hydrogen succinate ions.

Critical exponents and the universality class of a minesweeper percolation model

2020 ◽  
Vol 31 (09) ◽  
pp. 2050129
Author(s):  
Yuqi Qing ◽  
Wen-Long You ◽  
Maoxin Liu
Keyword(s):  
Phase Transition ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Critical Exponents ◽  
Critical Density ◽  
Universality Class ◽  
Percolation Model ◽  
System Configuration ◽  
Percolation Transition ◽  
Second Order Phase Transition

We introduce a minesweeper percolation model, in which the system configuration is obtained via an automatic minesweeper process. For a variety of candidate networks with different lattice configurations, our process gives rise to a second-order phase transition. Using Monte Carlo simulation, we identify the critical points implied by giant components. A set of critical exponents are extracted to characterize the nature of the minesweeper percolation transition. The determined universality class shows a clear difference from the traditional percolation transition. A proper mine density of the minesweeper game should be set around the critical density.

CRITICAL BEHAVIOR OF THE SPECIFIC HEAT IN THE VICINITY OF THE TRANSITION TEMPERATURE FOR S-TRIAZINE

2009 ◽  
Vol 23 (09) ◽  
pp. 2253-2259 ◽  
Author(s):  
M. KURT ◽  
H. YURTSEVEN
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Transition Temperature ◽  
Critical Exponent ◽  
Specific Heat ◽  
Power Law ◽  
Order Phase Transition ◽  
Critical Behavior ◽  
First Order ◽  
Second Order Phase Transition

The critical behavior of the specific heat is studied in s-triazine ( C 3 N 3 H 3). Using the experimental data for the CP, the temperature dependence of the specific heat is analyzed according to a power-law formula and the values of the critical exponent for CP are extracted in the vicinity of the transition temperature (TC=198.07 K ). It is indicated that s-triazine undergoes a weakly first order (quasi-continuous) or second order phase transition.

scholarly journals Magnetocaloric effect and critical behavior near the first to second-order phase transition of La0.7Ca0.3−xSnxMnO3 compounds

2020 ◽  
Vol 7 (4) ◽  
pp. 046101
Author(s):  
Dao Son Lam ◽  
Nguyen Thi Dung ◽  
Tran Dang Thanh ◽  
Dinh Chi Linh ◽  
Wen-Zhe Nan ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetocaloric Effect ◽  
Order Phase Transition ◽  
Critical Behavior ◽  
Second Order ◽  
Second Order Phase Transition

CRITICAL BEHAVIOR IN THE MODEL OF RANDOM SURFACES WITH DYNAMICAL HOLES EMBEDDED IN −2- AND 1-DIMENSIONAL SPACES

1991 ◽  
Vol 06 (01) ◽  
pp. 79-87 ◽  
Author(s):  
D.V. BOULATOV
Keyword(s):  
Phase Transition ◽  
Critical Behavior ◽  
Critical Exponents ◽  
Random Surfaces ◽  
Scalar Particles ◽  
Exactly Solvable ◽  
The Mean

The model of discretized random surfaces with dynamical holes recently proposed by V.A. Kazakov for D=0 is considered for nontrivial embeddings, the cases D=−2 and 1 being exactly solvable. The model has two new parameters: the fugacity for the number of the holes ξ and a mass of scalar particles moving along their borders m. At m=mc the mean length of the borders and the mean number of the holes undergo the phase transition — related to an explosion of the holes — becoming singular at ξ=0. The singularity still exists for m<mc where the phase of “completely torn” surfaces takes place. The correspondent critical exponents are calculated.

scholarly journals Phase transition, critical behavior, and critical exponents of Myers-Perry black holes

2013 ◽  
Vol 88 (2) ◽  
Author(s):  
Mohammad Bagher Jahani Poshteh ◽  
Behrouz Mirza ◽  
Zeinab Sherkatghanad
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Critical Behavior ◽  
Critical Exponents

The Effect of Hydrogen on an Iron Based Amorphous Alloy

1981 ◽  
Vol 8 ◽  
Author(s):  
H. Shahani ◽  
H. Soderhjelm ◽  
Mats Nygren
Keyword(s):  
Hydrogen Content ◽  
Atomic Structure ◽  
Melt Spinning ◽  
Amorphous Structure ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Cooling Rates ◽  
X Ray ◽  
Amorphous Ribbons ◽  
Partial Pressures

ABSTRACTIn this· investigation we have systematically studied the brittleness and the atomic structure in an Fe(SiBC) alloy. Different amounts of hydrogen have been dissolved in the alloy. It has then been studied at different cooling rates.Hydrogen gas of different partial pressures was dissolved into the melt. The alloy was then rapidly quenched by a chill block melt spinning method. The cooling rates were changed by changing the velocity on the chilling roll. The brittleness and the atomic structure were examined by bending tests and x-ray diffraction.X-ray diffractions showed that the ribbons were amorphous when the cooling rate was sufficient. Amorphous ribbons without any hydrogen were ductile, crystalline ribbons of this alloy were brittle. The ribbons with dissolved hydrogen and amorphous structure were brittle even at small amounts of hydrogen. At the highest cooling rates the ribbons with low hydrogen content were ductile. There seems to be a connection between the hydrogen content and the amorphous ribbons ductility. The hydrogen content only has a slight influence to amorphous structure.

Critical Behavior of Antiphase Boundaries in Fe-A127% Close to the D03→B2 Order Phase Transition

1995 ◽  
Vol 398 ◽  
Author(s):  
D. Le Floc'h ◽  
A. Loiseau
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Quantitative Determination ◽  
Order Phase Transition ◽  
Critical Behavior ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Second Order Phase Transition

ABSTRACTIn this paper, we present the first quantitative determination of the divergence law of the correlation length ξ, when approaching the second order phase transition DO3→B2, by studying the behaviour of the APBs by transmission electron microscopy.

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