Transformations in theGd5(Si1.95Ge2.05)alloy induced by the temperature and magnetic-field cycling through the first-order magnetic-martensitic phase transition

2001 ◽  
Vol 63 (6) ◽  
Author(s):  
E. M. Levin ◽  
A. O. Pecharsky ◽  
V. K. Pecharsky ◽  
K. A. Gschneidner
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Martensitic Phase ◽  
First Order ◽  
Martensitic Phase Transition ◽  
Field Cycling

Effect of high magnetic field on the two-step martensitic-phase transition in Ni2MnGa

2000 ◽  
Vol 76 (1) ◽  
pp. 37-39 ◽  
Author(s):  
Yanwei Ma ◽  
S. Awaji ◽  
K. Watanabe ◽  
M. Matsumoto ◽  
N. Kobayashi
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
High Magnetic Field ◽  
Martensitic Phase ◽  
Martensitic Phase Transition

Magneto-Transport and Magnetic Properties of Ni-Mn-Ga

2008 ◽  
Vol 52 ◽  
pp. 207-213 ◽  
Author(s):  
Soma Banik ◽  
R. Rawat ◽  
P.K. Mukhopadhyay ◽  
B.L. Ahuja ◽  
Aparna Chakrabarti ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Stoichiometric Composition ◽  
Ferromagnetic State ◽  
Martensitic Phase ◽  
Magnetization Measurements ◽  
First Order ◽  
Heating And Cooling ◽  
Domain Structures ◽  
Martensitic Phase Transition

We report a detailed investigation of the magneto-transport and magnetic properties of Mn excess Ni-Mn-Ga using the resistivity and magnetization measurements. Magnetoresistance (MR) has been measured in the ferromagnetic state for different compositions in the austenitic, premartensitic and martensitic phases. With Mn doping in Ni2-yMn1+yGa, a decrease in magnetization and MR has been found, since the doped Mn atoms in Ni position are in the antiferromagnetic configuration with the Mn atoms in Mn position. MR for the parent stoichiometric composition Ni2MnGa varies almost linearly with field in the austenitic and pre-martensitic phases, and shows a cusp-like shape in the martensitic phase. This has been explained by the changes in twin and domain structures in the martensitic phase. Hysteresis in the heating and cooling cycles is a characteristic of the first order nature of the martensitic phase transition.

INFLUENCE OF AN EXTERNAL MAGNETIC FIELD ON THE DYNAMICS OF A NEW-PHASE NUCLEUS IN THE VICINITY OF THE FIRST-ORDER PHASE TRANSITION IN MAGNETS WITH DEFECTS PRESENT

2012 ◽  
Vol 26 (28) ◽  
pp. 1250183 ◽  
Author(s):  
VLADIMIR NAZAROV ◽  
RISHAT SHAFEEV
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Magnetic Anisotropy ◽  
Spin Reorientation ◽  
Critical Fields ◽  
First Order ◽  
Phase Nucleus ◽  
First Order Phase Transition ◽  
New Phase

Theoretically, with the aid of a soliton model, the evolution of a new-phase nucleus near the first-order spin-reorientation phase transition in magnets has been investigated in an external magnetic field. The influence of an external field and one-dimensional defects of magnetic anisotropy on the dynamics of such nucleus has been demonstrated. The conditions for the localization of the new-phase nucleus in the region of the magnetic anisotropy defect and for its escape from the defect have been determined. The values of the critical fields which bring about the sample magnetization reversal have been identified and estimated.

scholarly journals Phase Transition in Iron Thin Films Containing Coherent Twin Boundaries: A Molecular Dynamics Approach

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3631 ◽  
Author(s):  
Binjun Wang ◽  
Yunqiang Jiang ◽  
Chun Xu
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Molecular Dynamics ◽  
Free Surface ◽  
Transition Temperature ◽  
Film Thickness ◽  
Martensitic Phase ◽  
Martensitic Transition ◽  
Twin Boundaries ◽  
Martensitic Phase Transition

Using molecular dynamics (MD) simulation, the austenitic and martensitic phase transitions in pure iron (Fe) thin films containing coherent twin boundaries (TBs) have been studied. Twelve thin films with various crystalline structures, thicknesses and TB fractions were investigated to study the roles of the free surface and TB in the phase transition. In the austenitic phase transition, the new phase nucleates mainly at the (112)bcc TB in the thicker films. The (111¯)bcc free surface only attends to the nucleation, when the film is extremely thin. The austenitic transition temperature shows weak dependence on the film thickness in thicker films, while an obvious transition temperature decrease is found in a thinner film. TB fraction has only slight influence on the austenitic temperature. In the martensitic phase transition, both the (1¯10)fcc free surface and (111)fcc TB attribute to the new body-center-cubic (bcc) phase nucleation. The martensitic transition temperature increases with decreased film thickness and TB fraction does not influent the transition temperature. In addition, the transition pathways were analyzed. The austenitic transition obeys the Burgers pathway while both the Kurdjumov–Sachs (K–S) and Nishiyama–Wassermann (N–W) relationship are observed in the martensitic phase transition. This work may help to understand the mechanism of phase transition in the Fe nanoscaled system containing a pre-existing defect.

Thermodynamic properties of a spin-1 model with long-range interactions

2018 ◽  
Vol 32 (05) ◽  
pp. 1850053 ◽  
Author(s):  
Ji-Xuan Hou ◽  
Xu-Chen Yu
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Diagram ◽  
Long Range ◽  
Order Phase Transition ◽  
First Order ◽  
First Order Phase Transition ◽  
Long Range Interactions ◽  
External Magnetic Field Strength ◽  
First Order Phase

The long-range interacting spin-1 chain placed in a staggered magnetic field is studied by means of microcanonical approach. Firstly, we study the microcanonical entropy of the system in the thermodynamic limit and find the system is non-ergodic and can exhibit either first-order phase transition or second-order phase transition by shifting the external magnetic field strength. Secondly, we construct the global phase diagram of the system and find a phase transition area in the phase diagram corresponding to the temperature jump of the first-order phase transition.

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