Study of martensitic transition temperature on NiFeGaX Heusler glass-coated microwires doped by X = B, Al, Ga, In

2021 ◽  
pp. 168605
Author(s):  
M. Hennel ◽  
L. Galdun ◽  
T. Ryba ◽  
R. Varga
Keyword(s):  
Transition Temperature ◽  
Martensitic Transition

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.

Temperature dependence of the elastic constants above the martensitic transition temperature in Cu-15.0 at% Sn alloy

1978 ◽  
Vol 12 (3) ◽  
pp. 271-275 ◽  
Author(s):  
N. Nakanishi ◽  
M. Takano ◽  
M. Hashimoto ◽  
H. Morimoto ◽  
S. Miura
Keyword(s):  
Transition Temperature ◽  
Temperature Dependence ◽  
Elastic Constants ◽  
Martensitic Transition

scholarly journals Phase Transitions and Magnetocaloric Properties in MnCo1−xZrxGe Compounds

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Anil Aryal ◽  
Abdiel Quetz ◽  
Sudip Pandey ◽  
Igor Dubenko ◽  
Shane Stadler ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Ferromagnetic State ◽  
Partial Substitution ◽  
Cooling Power ◽  
Martensitic Transition ◽  
Ferromagnetic Transition ◽  
Scanning Calorimetry ◽  
Magnetostructural Transition ◽  
Magnetocaloric Properties ◽  
Single Transition

The structural, magnetic, and magnetocaloric properties of MnCo1-xZrxGe (0.01≤x≤0.04) have been studied through X-ray diffraction, differential scanning calorimetry, and magnetization measurements. Results indicate that the partial substitution of Zr for Co in MnCo1-xZrxGe decreases the martensitic transition temperature (TM). For x = 0.02, TM was found to coincide with the ferromagnetic transition temperature (TC) resulting in a first-order magnetostructural transition (MST). A further increase in zirconium concentration (x = 0.04) showed a single transition at TC. The MST from the paramagnetic to ferromagnetic state results in magnetic entropy changes (-ΔSM) of 7.2 J/kgK for ΔH = 5 T at 274 K for x = 0.02. The corresponding value of the relative cooling power (RCP) was found to be 266 J/kg for ΔH = 5 T. The observed large value of MCE and RCP makes this system a promising material for magnetic cooling applications.

scholarly journals Structural, Thermal and Magnetic Properties of Ga Excess Ni-Mn-Ga

2009 ◽  
Vol 635 ◽  
pp. 43-47 ◽  
Author(s):  
Sanjay Singh ◽  
S. Bhardwaj ◽  
A.K. Panda ◽  
V.K. Ahire ◽  
Amitava Mitra ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Magnetic Properties ◽  
Transition Temperature ◽  
Martensitic Transition ◽  
Martensitic Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ga Doping ◽  
Heat Of Transformation

The martensitic transition and the ferro- to paramagnetic transition have been studied in a series of Ga excess Ni-Mn-Ga specimens [Ni2-xMnGa1+x (0.4≤ x≤ 0.9)] by differential scanning calorimetry and magnetization measurements. The martensitic transition exhibits a hysteresis whose width is similar to Ni2MnGa, indicating that the transition is thermoelastic. The latent heat of transformation is comparable with other Ni-Mn-Ga alloys. A substantial increase in the martensitic transition temperature is observed due to Ga doping. Interestingly, the x-ray diffraction pattern of all the compositions studied show a modulated martensitic structure in the martensitic phase.

scholarly journals Full Variation of Site Substitution in Ni-Mn-Ga by Ferromagnetic Transition Metals

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 850
Author(s):  
Vít Kopecký ◽  
Michal Rameš ◽  
Petr Veřtát ◽  
Ross H. Colman ◽  
Oleg Heczko
Keyword(s):  
Transition Temperature ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Transformation Temperature ◽  
Bulk Material ◽  
Martensitic Transition ◽  
Ferromagnetic Transition ◽  
Transition Elements ◽  
Martensitic Transformation Temperature ◽  
Valence Electrons

Systematic doping by transition elements Fe, Co and Ni on each site of Ni2MnGa alloy reveal that in bulk material the increase in martensitic transformation temperature is usually accompanied by the decrease in ferromagnetic Curie temperature, and vice versa. The highest martensitic transformation temperature (571 K) was found for Ni50.0Mn25.4(Ga20.3Ni4.3) with the result of a reduction in Curie temperature by 55 K. The highest Curie point (444 K) was found in alloy (Ni44.9Co5.1)Mn25.1Ga24.9; however, the transition temperature was reduced to 77 K. The dependence of transition temperature is better scaled with the Ne/a parameter (number of non-bonding electrons per atom) compared to usual e/a (valence electrons per atom). Ne/a dependence predicts a disappearance of martensitic transformation in (Ni45.3Fe5.3)Mn23.8Ga25.6, in agreement with our experiment. Although Curie temperature usually slightly decreases while the martensitic transition increases, there is no significant correlation of Curie temperature with e/a or Ne/a parameters. The doping effect of the same element is different for each compositional site. The cascade substitution is discussed and related to the experimental data.

Signature of Austenitic to Martensitic Phase Transition in Ni2MnGa in Mn and Ni K-Edge XANES Spectra

2008 ◽  
Vol 52 ◽  
pp. 175-180 ◽  
Author(s):  
V.G. Sathe ◽  
Soma Banik ◽  
Aditi Dubey ◽  
S.R. Barman ◽  
A.M. Awasthi ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Low Temperatures ◽  
Electronic States ◽  
Peak Height ◽  
Martensitic Phase ◽  
Martensitic Transition ◽  
Strong Correlations ◽  
Austenitic Phase ◽  
Martensitic Phase Transition ◽  
Edge Features

The XANES studies at Mn, Ni and Ga K-edge of Ni2MnGa compound have been carried out at room and low temperatures. The Mn K-edge and Ni K-edge spectra shows modulation in the post edge features when the sample is cooled below martensitic transition temperature. It is strongly reflected in the XANES of Mn K-edge where the peak after the edge gets totally suppressed when the sample is in martensitic phase. This peak shows a hysteretic behaviour when thermal cycling was done across the martensitic transition temperature. This clearly shows that the peak height is a measure of austenitic phase present at a particular temperature. This demonstrates the strong correlations of electronic states and crystal structures in these compounds.

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