scholarly journals A case study of Fe2TaZ (Z = Al, Ga, In) Heusler alloys: hunt for half-metallic behavior and thermoelectricity

RSC Advances ◽  
2018 ◽  
Vol 8 (71) ◽  
pp. 40996-41002 ◽  
Author(s):  
Shakeel Ahmad Khandy ◽  
Ishtihadah Islam ◽  
Dinesh C. Gupta ◽  
Muzzammil Ahmad Bhat ◽  
Shabir Ahmad ◽  
...  

Crystal structure in conventional unit cell for Fe2TaZ (Z = Al, Ga, In) in Fm3̄m configuration.

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
R. Mahat ◽  
S. KC ◽  
U. Karki ◽  
J. Y. Law ◽  
V. Franco ◽  
...  

2020 ◽  
Vol 62 (1) ◽  
pp. 1-14
Author(s):  
A. Maafa ◽  
H. Rozale ◽  
A. Oughilas ◽  
A. Boubaça ◽  
A. Amar ◽  
...  

AbstractIn the purpose of exploring new Heusler alloys with different magnetic applications, we have employed first principles calculations method within density functional theory. After checking the structural stability of X2YZ Heusler alloys (X = Fe, Co; Y =Zr, Mo and Z = Ge, Sb), we found that Cu2MnAl type structure is more favorable for most compounds except for X2MoGe and Co2MoSb, were the Hg2CuTi structure is energetically more stable. The trends in magnetic and electronic structures can be predicted by the structure types as well as the different kinds of hybridizations between the constituents. Among the two series only two compounds were identified to be true half metals with potential applications in spintronic devices. While one compound was classified as a nonmagnetic semiconductor with a small band gap. For the rest of materials, we found that the metallic behavior is dominant. These materials show possible interesting features in technical applications as well. The effect of distortion on the magnetic properties of Co2ZrGe and Fe2ZrSb showed that the half metallic character was preserved within a moderate range of volume changes, which makes it possible to grow these materials as thin films with modern techniques.


2020 ◽  
Vol 820 ◽  
pp. 153373 ◽  
Author(s):  
S. Idrissi ◽  
S. Ziti ◽  
H. Labrim ◽  
L. Bahmad ◽  
I. El Housni ◽  
...  

2020 ◽  
Vol 62 (1) ◽  
pp. 95-107
Author(s):  
F. Issaad ◽  
A. Maafa ◽  
H. Rozale ◽  
M.A. Boukli Hacene ◽  
A. Bouabça

AbstractIn this paper, we have studied the electronic, elastic and thermoelectric properties of the half-Heusler LiCrZ (Z = C, N, Si, and P) materials in Type II phase, in this structure the atomic occupations are X (1/2,1/2,1/2), Y (0,0,0) and Z(1/4,1/4,1/4). The ferromagnetic state of Type II structure was found to be the most stable phase for all studied alloys. After calculating the elastic constants, we found out that the conditions of mechanical stability were verified only for LiCrSi and LiCrP alloys in Type II phase, at both equilibrium a0 and half metallic ahm lattice constants, which indicates that these two compounds can be synthesized experimentally. We should also mention that the half metallic behavior in Type II structure, for LiCrSi and LiCrP compounds, was obtained by straining the equilibrium lattice constants by 2% and 6%, respectively. At ahm, these two systems were identified to be true half metals due to their complete spin polarization and integer value of total magnetic moment. These last ones have reached 3μB per unit cell when Z = Si, and 4μB when Z = P. Using the mean field approximation (MFA), the Curie temperatures of Type II structure were also determined, where the values are estimated to be 456.2 K and 302.8 K, respectively. Finally, the thermoelectric performance has been explored by the classical Boltzmann theory. At low temperatures, the figure of merit has reached 0.73 and 0.93 for LiCrSi and LiCrP, respectively. The considerable ZT values and all calculated physical properties make these two systems promising candidates for thermoelectric applications.


2021 ◽  
Vol 63 (11) ◽  
pp. 1751
Author(s):  
Д.Р. Байгутлин ◽  
В.В. Соколовский ◽  
О.Н. Мирошкина ◽  
В.Д. Бучельников

The properties of Heusler alloys of the Mn2ScZ family (Z = Al, Si, P, Ga, Ge, As, In, Sn, Sb) are investigated within the framework of the density functional theory. The PBE GGA and meta-GGA SCAN functionals were used for approximation of the exchange-correlation interactions. Calculations show that PBE does not predict ideal half-metallic behavior, unlike SCAN. It is shown that at Z = P, Si, a transition from the half-metallic state to the metallic one is observed. This effect can be used to develop tunable spintronic devices.


Author(s):  
H. Brigitte Krause ◽  
Yonglin Qian

A polycrystalline specimen of nominal formula EuGaAl with unknown crystal structure was investigated by various electron microscope techniques; EDS-, SED-, and CBED data were taken on a Philips 400 electron microscope operated at 100kV, HREM data on a Hitachi 9000 microscope operated at 300kV. The EDS data confirmed the composition for the bulk of the material but, in addition, revealed particles with other fractions of the elements. Only the EuGaAl particles were further investigated. The unit cell was determined to be orthorhombic with a ratio: a/b=0.969(2) , a/c=0.234(2) and b/c=0.234(2). The lattice constants are a=4.54(5)Ȧ, b=4.68Ȧ and c=19.97(20)Ȧ. Based on systematic extinctions for hkl reflections with h+l=2n+l, the unit cell was found to be b-centered. CBED patterns of the [001], [100], and [010] zone axes are shown in Fig. 1. The zone axis patterns are in agreement with the above stated data except for diffused (2m+l,2n+l,0)- reflections, not compatible with the above stated systematic absences. But these occurred only occasionally in conjunction with a complicated noncommensurate superlattice pattern.


2021 ◽  
Vol 53 (6) ◽  
Author(s):  
Malika Hachemaoui ◽  
Mohamed Meskine ◽  
Allel Mokaddem ◽  
Bendouma Doumi ◽  
Yesim Mogulkoc ◽  
...  

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