scholarly journals Magnetocaloric Effect, Magnetoresistance of Sc0.28Ti0.72Fe2, and Phase Diagrams of Sc0.28Ti0.72Fe2−xTx Alloys with T = Mn or Co

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 410 ◽  
Author(s):  
Liting Sun ◽  
Hargen Yibole ◽  
Ojiyed Tegus ◽  
Francois Guillou

(Sc,Ti)Fe2 Laves phases present a relatively unique case of first-order ferro-ferromagnetic transition originating from an instability of the Fe moment. In addition to large magnetoelastic effects making them potential negative thermal expansion materials, here, we show that Sc0.28Ti0.72Fe2 and related alloys also present sizable magnetocaloric and magnetoresistance effects. Both effects are found substantially larger at the ferro-ferromagnetic transition (Tt1) than near the Curie temperature TC, yet they remain limited in comparison to other classes of giant magnetocaloric materials. We suggest a strategy to improve these properties by bringing the transition at Tt1 close to TC, and test its possible realization by Co or Mn for Fe substitutions. The structural and magnetic phase diagrams of Sc0.28Ti0.72Fe2−xTx alloys with T = Mn or Co are explored. Substitutions for Fe by adjacent Mn or Co elements give rise to a breakdown of the long-range ferromagnetic order, as well as a swift disappearance of finite moment magnetism.

2021 ◽  
Vol 7 (5) ◽  
pp. 60
Author(s):  
Luis M. Moreno-Ramírez ◽  
Victorino Franco

The applicability of magnetocaloric materials is limited by irreversibility. In this work, we evaluate the reversible magnetocaloric response associated with magnetoelastic transitions in the framework of the Bean-Rodbell model. This model allows the description of both second- and first-order magnetoelastic transitions by the modification of the η parameter (η<1 for second-order and η>1 for first-order ones). The response is quantified via the Temperature-averaged Entropy Change (TEC), which has been shown to be an easy and effective figure of merit for magnetocaloric materials. A strong magnetic field dependence of TEC is found for first-order transitions, having a significant increase when the magnetic field is large enough to overcome the thermal hysteresis of the material observed at zero field. This field value, as well as the magnetic field evolution of the transition temperature, strongly depend on the atomic magnetic moment of the material. For a moderate magnetic field change of 2 T, first-order transitions with η≈1.3−1.8 have better TEC than those corresponding to stronger first-order transitions and even second-order ones.


APL Materials ◽  
2017 ◽  
Vol 5 (10) ◽  
pp. 106102 ◽  
Author(s):  
Fei-Ran Shen ◽  
Hao Kuang ◽  
Feng-Xia Hu ◽  
Hui Wu ◽  
Qing-Zhen Huang ◽  
...  

1980 ◽  
Vol 22 (10) ◽  
pp. 2447-2464 ◽  
Author(s):  
J. B. Kogut ◽  
R. B. Pearson ◽  
J. Shigemitsu ◽  
D. K. Sinclair

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