An ab initio study of Co–Cr(V) disorder effects on the electronic structure and magnetic properties of

Li, Q.F.; Zhao, Hongze; Wang, Lu

doi:10.1016/j.ssc.2009.09.039

Cited by 4 publications

(2 citation statements)

References 30 publications

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“…Disorder can transform the * rsdhaka@physics.iitd.ac.in L2 1 structure to B2 type (disorder between Y and Z atoms) or A2 type (disorder between X, Y, and Z atoms). In case of the Co 2 CrAl alloy, the increasing Co-Cr type disorder [12,16,17] can drastically reduce the spin polarization and therefore the total magnetic moment due to an antiferromagnetic coupling of the antisite Cr with the first-nearest-neighbor ordinary-site Cr and Co atoms [18,19]. With this respect, using powder neutron-diffraction (ND) technique, Mukadam et al quantified the site disorder and studied its effect on the spin polarization of the NiFeMnSn Heusler alloy, which is predicted to show nearly half-metallic nature in band-structure calculations [20].…”

Section: Introductionmentioning

confidence: 99%

Neutron diffraction and magnetic properties of Co2Cr1−xTixAl Heusler alloys

et al. 2019

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We report the structural, magnetic, and magnetocaloric properties of Co 2 Cr 1−x Ti x Al (x = 0-0.5) Heusler alloys for spintronic and magnetic refrigerator applications. Room-temperature x-ray diffraction and neutron diffraction patterns along with Rietveld refinements confirm that the samples are of single phase and possess a cubic structure. Interestingly, magnetic susceptibility measurements indicate a second-order phase transition from paramagnetic to ferromagnetic where the Curie temperature (T C ) of Co 2 CrAl increases from 330 K to 445 K with Ti substitution. Neutron powder diffraction data of the x = 0 sample across the magnetic phase transition taken in a large temperature range confirm the structural stability and exclude the possibility of antiferromagnetic ordering. The saturation magnetization of the x = 0 sample is found to be 8000 emu/mol (1.45 μ B /f.u.) at 5 K, which is in good agreement with the value (1.35 ± 0.05 μ B /f.u.) obtained from the Rietveld analysis of the neutron powder diffraction pattern measured at a temperature of 4 K. By analyzing the temperature dependence of the neutron data of the x = 0 sample, we find that the change in the intensity of the most intense Bragg peak ( 220) is consistent with the magnetization behavior with temperature. Furthermore, an enhancement of change in the magnetic entropy and relative cooling power values has been observed for the x = 0.25 sample. Interestingly, the critical behavior analysis across the second-order magnetic phase transition and extracted exponents (β ≈ 0.496, γ ≈ 1.348, and δ ≈ 3.71 for the x = 0.25 sample) suggest the presence of long-range ordering, which deviates toward 3D Heisenberg-type interactions above T C , consistent with the interaction range value σ .

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Section: Introductionmentioning

confidence: 99%

Neutron diffraction and magnetic properties of Co2Cr1−xTixAl Heusler alloys

et al. 2019

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“…Disorder can transform the L2 1 structure to B2 type (disorder between Y and Z atoms) or A2 type (disorder between X, Y and Z atoms). In case of the Co 2 CrAl alloy, the increasing Co-Cr type disorder [12,16,17] can drastically reduce the spin polarization and therefore the total magnetic moment due to an antiferromagnetic coupling of the antisite Cr with the first nearest-neighbor ordinary-site Cr and Co atoms [18,19]. With this respect, using powder neutron diffraction technique Mukadam et al quantified the site disorder and studied its effect on the spin polarization of the NiFeMnSn Heusler alloy, which is predicted to show nearly half-metallic nature in band structure calculations [20].…”

Section: Introductionmentioning

confidence: 99%

Neutron diffraction and magnetic properties of Co$_2$Cr$_{1-x}$Ti$_x$Al Heusler alloys

Nehla,

Kareri,

Gupt

et al. 2019

Preprint

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We report the structural, magnetic, and magnetocaloric properties of Co2Cr1−xTixAl (x = 0-0.5) Heusler alloys for spintronic and magnetic refrigerator applications. Room temperature X-ray diffraction and neutron diffraction patterns along with Rietveld refinements confirm that the samples are of single phase and possess a cubic structure. Interestingly, magnetic susceptibly measurements indicate a second order phase transition from paramagnetic to ferromagnetic where the Curie temperature (TC) of Co2CrAl increases from 330 K to 445 K with Ti substitution. Neutron powder diffraction data of the x = 0 sample across the magnetic phase transition taken in a large temperature range confirm the structural stability and exclude the possibility of antiferromagnetic ordering. The saturation magnetization of the x = 0 sample is found to be 8000 emu/mol (1.45 µB/f.u.) at 5 K, which is in good agreement with the value (1.35±0.05 µB/f.u.) obtained from the Rietveld analysis of the neutron powder diffraction pattern measured at temperature of 4 K. By analysing the temperature dependence of the neutron data of the x = 0 sample, we find that the change in the intensity of the most intense Bragg peak ( 220) is consistent with the magnetization behavior with temperature. Furthermore, an enhancement of change in the magnetic entropy and relative cooling power values has been observed for the x = 0.25 sample. Interestingly, the critical behavior analysis across the second order magnetic phase transition and extracted exponents (β ≈ 0.496, γ ≈ 1.348, and δ ≈ 3.71 for the x = 0.25 sample) suggest the presence of long-range ordering, which deviates towards 3D Heisenberg type interactions above TC, consistent with the interaction range value σ.

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