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X-ray photoelectron spectroscopy and magnetism of Mn1−x Alx alloys

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Rednic V., Rednic L., Coldea M., Pop V., Neumann M., Pacurariu R., Tunyagi A.

Open Physics

2008

vol. 6

issue 3

434-439

X-ray photoelectron spectroscopy (XPS), magnetization and magnetic susceptibility of Mn1−x Alx (x = 0.0, 0.2, 0.4, 0.5, 0.6, 0.7) alloys are reported. X-ray diffraction measurements showed that all investigated samples have the same crystallographic structure as the parent compound (AuCu3-structure type). The alloys are disordered for x ≤ 0.5, but become almost crystallographically ordered for higher Al concentration. This change in the crystallographic order is reflected both in the magnetization and Curie temperature values. The exchange interaction is ferromagnetic between the pairs of the near-neighbour Mn-Ni and Ni-Ni magnetic moments and antiferromagnetic for Mn-Mn pairs. The last one is present only in the disordered alloys, which leads to smaller values of the magnetization of these alloys in comparison with the ordered ones. The Mn magnetic moment has the fully ordered value of 3.2 μB in all investigated alloys. The decrease of the Ni magnetic moment as the Al concentration increases may be explained by the hybridization of the Ni 3d and Al 3sp states, which leads to a partial filling of the Ni 3d band. The magnetic susceptibility measurements pointed out the existence of spin fluctuations on Ni sites.

Electronic and optical properties of ZnSxSe1âˆ’x alloys

100%

Feng Z., Hu H., Cui S.

Open Physics

2009

vol. 7

issue 2

340-344

A series of calculations from first principles have been carried out to study structural, electronic, and optical properties of ZnSxSe1âˆ’x alloys. Our results show that the lattice constant scales linearly with sulfur composition. The imaginary parts of the dielectric function are calculated, which are in good agreement with the experimental data. We have also interpreted the origin of the spectral peaks on the basis of band structure and density of states. Additionally, we find that no bowing effect in the absorption edge is observed, unlike other II-VI semiconductor alloys.

Electronic Structure and Magnetic Exchange Interaction in Fe₂NiAs Compound

100%

Wei X.-P., Zhang Y.-L., Sun X.-W., Song T., Zhu X.-F.

Using the spin-polarized relativistic Korringa-Kohn-Rostoker method, we study the electronic and magnetic properties of Fe₂NiAs compound with the Hg₂CuTi structure. Electronic calculations reveal the d-d orbital hybridization taking an important role in the compound. The calculated magnetic moments, which contain the spin and orbital moments, are primarily carried by Fe atoms located in A and B sites. The orbital moment of Fe₂NiAs system is rather small due to the cause of orbital quenching, implying a weak spin-orbit coupling. Simultaneously, we also study the influence of lattice constant on the magnetic moment, it is found that both spin and orbital moments are sensitive to the changes of lattice constants, i.e., the moments become larger as the expansion of lattice constant, indicating the enhancement of spin-orbit coupling effect. In addition, we investigate the magnetic interactions between the constituents to obtain the Heisenberg exchange coupling parameters. It is noted that the interactions are dominated by a strong exchange between Fe atoms. Finally, we acquire the Curie temperatures of Fe₂NiAs compound under different lattice constants by using mean field approximation.

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2 Open Physics

1 Acta Physica Polonica A

1 2017

1 2009

1 2008

1 Coldea M.

1 Cui S.

1 Feng Z.

1 Hu H.

1 Neumann M.

1 Pacurariu R.

1 Pop V.

1 Rednic L.

1 Rednic V.

1 Song T.

1 Sun X.-W.

1 Tunyagi A.

1 Wei X.-P.

1 Zhang Y.-L.

1 Zhu X.-F.

Search results

X-ray photoelectron spectroscopy and magnetism of Mn1−x Alx alloys

Electronic and optical properties of ZnSxSe1âˆ’x alloys

Electronic Structure and Magnetic Exchange Interaction in Fe₂NiAs Compound