Magnetocaloric Properties and Magnetic Anisotropy by Tailoring Phase Transitions in NiMnGa Alloys

2008 ◽  
Vol 583 ◽  
pp. 169-196 ◽  
Author(s):  
Franca Albertini ◽  
Massimo Solzi ◽  
Antonio Paoluzi ◽  
Lara Righi
Keyword(s):  
Magnetic Anisotropy ◽  
Magnetocaloric Effect ◽  
Magnetic Transition ◽  
Critical Temperatures ◽  
First Order ◽  
Magnetostructural Transition ◽  
Thermomagnetic Analysis ◽  
Magnetocaloric Properties ◽  
Giant Magnetocaloric Effect ◽  
Composition Changes

The giant magnetocaloric properties of NiMnGa alloys can be enhanced by suitable composition changes that make structural and magnetic transition temperatures to coincide. In this paper we report results on critical temperatures, magnetic anisotropy, and magnetocaloric effect in Ni- and Mn-rich alloys as a function of composition. A phenomenological phase diagram, useful for the identification by thermomagnetic analysis of magnetic and structural transitions in the vicinity of their coincidence, is proposed. Particular emphasis is given to the discussion of giant magnetocaloric effect of those alloys showing a first order magnetostructural transition, the method of its determination, and the potentialities for applications in the field of magnetic refrigeration.

Giant magnetocaloric effect of MnAs1−xSbx in the vicinity of first-order magnetic transition

2003 ◽  
Vol 328 (1-2) ◽  
pp. 114-116 ◽  
Author(s):  
H. Wada ◽  
T. Morikawa ◽  
K. Taniguchi ◽  
T. Shibata ◽  
Y. Yamada ◽  
...  
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Transition ◽  
First Order ◽  
Giant Magnetocaloric Effect

scholarly journals Influence of the transition width on the magnetocaloric effect across the magnetostructural transition of Heusler alloys

2016 ◽  
Vol 374 (2074) ◽  
pp. 20150306 ◽  
Author(s):  
F. Cugini ◽  
G. Porcari ◽  
S. Fabbrici ◽  
F. Albertini ◽  
M. Solzi
Keyword(s):  
Magnetocaloric Effect ◽  
Heusler Alloys ◽  
Entropy Change ◽  
Large Temperature ◽  
Transition Width ◽  
Critical Temperatures ◽  
Magnetostructural Transition ◽  
Magnetocaloric Properties ◽  
Clear Result ◽  
Effective Use

We report a complete structural and magneto-thermodynamic characterization of four samples of the Heusler alloy Ni-Co-Mn-Ga-In, characterized by similar compositions, critical temperatures and high inverse magnetocaloric effect across their metamagnetic transformation, but different transition widths. The object of this study is precisely the sharpness of the martensitic transformation, which plays a key role in the effective use of materials and which has its origin in both intrinsic and extrinsic effects. The influence of the transition width on the magnetocaloric properties has been evaluated by exploiting a phenomenological model of the transformation built through geometrical considerations on the entropy versus temperature curves. A clear result is that a large temperature span of the transformation is unfavourable to the magnetocaloric performance of a material, reducing both isothermal entropy change and adiabatic temperature change obtainable in a given magnetic field and increasing the value of the maximum field needed to fully induce the transformation. The model, which is based on standard magnetometric and conventional calorimetric measurements, turns out to be a convenient tool for the determination of the optimum values of transformation temperature span in a trade-off between sheer performance and amplitude of the operating range of a material. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’.

scholarly journals Influence of structural defects on the magnetocaloric effect in the vicinity of the first order magnetic transition in Fe50.4Rh49.6

2016 ◽  
Vol 108 (19) ◽  
pp. 192405 ◽  
Author(s):  
V. I. Zverev ◽  
A. M. Saletsky ◽  
R. R. Gimaev ◽  
A. M. Tishin ◽  
T. Miyanaga ◽  
...  
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Transition ◽  
Structural Defects ◽  
First Order

scholarly journals Магнитокалорический эффект в окрестности температуры магнитной компенсации аморфных ферримагнитных пленок Gd-Co

2021 ◽  
Vol 63 (9) ◽  
pp. 1325
Author(s):  
А.В. Свалов ◽  
А.В. Архипов ◽  
В.Н. Лепаловский ◽  
Е.А. Степанова ◽  
В.О. Васьковский ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Anisotropy ◽  
Magnetocaloric Effect ◽  
Magnetic Structure ◽  
Perpendicular Magnetic Anisotropy ◽  
Film Plane ◽  
Probable Reason ◽  
Wide Range ◽  
Magnetocaloric Properties ◽  
The Magnetic Field

The magnetic and magnetocaloric properties of amorphous ferrimagnetic Gd-Co films with perpendicular magnetic anisotropy were studied in a wide range of fields and temperatures. The change in the sign of the magnetocaloric effect near the compensation temperature occurs almost abruptly when the magnetic field is oriented perpendicular to the film plane. In a certain temperature range, it happens when the field is oriented along the plane of the sample. The most probable reason for the blurring of this transition is the appearance of a non-collinear magnetic structure.

First-Order Phase Transition and Magnetocaloric Effect of MnFeP0.63Ge0.12Si0.25 Compound

2014 ◽  
Vol 1053 ◽  
pp. 37-40
Author(s):  
Gao Feng Wang ◽  
Zeng Ru Zhao ◽  
Xiao Bin Zhang ◽  
Xue Feng Zhang
Keyword(s):  
Phase Transition ◽  
Magnetocaloric Effect ◽  
First Order ◽  
Heating And Cooling ◽  
First Order Phase Transition ◽  
Potential Applications ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Giant Magnetocaloric Effect ◽  
P Type

In this paper, the magnetic phase transition and magnetocaloric effect have been investigated in the Fe2P-type MnFeP0.63Ge0.12Si0.25compound. The X-ray diffraction patterns measured at different temperatures indicate that the crystal structure remains and the lattice parameters change sharply near the transition temperature when a phase transition takes place. The isofield magnetization curves on heating and cooling and the Arrott plots reveal that the nature of the transition is first order. The characteristic of giant magnetocaloric effect results from the field-induced first-order metamagnetic phase transition, which makes the compound having potential applications in magnetic refrigeration.

Direct Measurements of Magnetocaloric Effect in a Single Crystalline Ni2.13Mn0.81Ga1.06 Heusler Alloy

2016 ◽  
Vol 872 ◽  
pp. 38-42
Author(s):  
Vladimir Khovaylo ◽  
Konstantin Skokov ◽  
Sergey Taskaev ◽  
Alexey Karpenkov ◽  
Dmitriy Karpenkov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Magnetocaloric Effect ◽  
Direct Method ◽  
Magnetic Transition ◽  
Martensitic Transformations ◽  
Austenitic Phase ◽  
Single Crystalline ◽  
First Order ◽  
Direct Measurements

Magnetocaloric effect (MCE) in the vicinity of first order martensitic transformation and second order magnetic transition in a single crystalline Ni2.13Mn0.81Ga1.06 Heusler compound was studied by a direct method. The obtained results revealed that, for the applied magnetic field strength μ0H = 1.9 T, MCE is irreversible in the vicinity of the first order martensitic transformation only when the MCE measurements are performed under cooling protocol. Plot of the experimentally measured adiabatic temperature change ΔTad as a function of temperature T indicated that ΔTad has a negligible benefit from the magnetic field-induced conversion of the high-temperature austenitic phase into the low-temperature martensitic phase and is mainly determined by the paraprocess of the austenitic phase around both direct and reverse martensitic transformations.

Sign in / Sign up

Export Citation Format

Share Document