Concentration Dependence of Magnetic Properties of Binary B.C.C. Alloys with Substitutional Disorder
E. G. Len$^{1}$, V. V. Lizunov$^{1}$, T. S. Len$^{2}$, M. V. Ushakov$^{1}$, V. A. Tatarenko$^{1}$
$^{1}$G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine
$^{2}$National Aviation University, 1 Cosmonaut Komarov Ave., 03058 Kyiv, Ukraine
Received: 03.09.2015. Download: PDF
The concentration dependences of the magnetic properties of binary b.c.c. alloys with substitutional disorder are investigated within the scope of the generalized single-band Hubbard model. The breaking of alloys’ translation invariance because of the atomic disorder leads to a violation of electron—hole symmetry, which results in both the threshold character of antiferromagnetic ordering at half filling and the asymmetry of alloys’ magnetic phase diagrams relative to corresponding value of average electron density per one site ($n = 1$). As found, a different advantageous order for filling the Hubbard subbands of the alloy components, A and B, with $n$ increasing, which is determined by sign of scattering potential of impurity, in the general case, results in an asymmetry (relative to point $P_{0}^{A} = 0.5$) of dependences of magnetic characteristics on the concentration $P_{0}^{A}$ of component A in isovalent alloys ($Z_{A} = Z_{B}$, $n = const$). The asymmetry of the same concentration dependences for the alloys with $Z_{A} = 1$, $Z_{B} = 0$ is caused by the relationship $P_{0}^{A} = n$. For these alloys, the observed concentration dependences of the localized magnetic moments are similar to the dependence of analogous one for pure metal, but with differences in the values of the magnetic moments for different alloy components and with the possibility of a distinct concentration dependence of magnetic order parameter. The concentration dependences of magnetic moments in alloys with $Z_{A} = 1$, $Z_{B} = 2$, as opposed to other types of alloys, are symmetric to a large degree. However, the concentration dependence of magnetic order parameter is asymmetric due to the violation of electron—hole symmetry with $n = 2P_{0}^{A}$ changing from 0 to 2.
Key words: magnetic alloys, electronic structure, strongly correlated electrons, magnetic phase diagram, localized magnetic moments, concentration dependence.
URL: http://mfint.imp.kiev.ua/en/abstract/v37/i10/1405.html
DOI: https://doi.org/10.15407/mfint.37.10.1405
PACS: 71.10.Fd,71.20.Be,71.27.+a,71.28.+d,71.55.Jv,75.10.Lp,75.30.Kz,75.40.Cx
Citation: E. G. Len, V. V. Lizunov, T. S. Len, M. V. Ushakov, and V. A. Tatarenko, Concentration Dependence of Magnetic Properties of Binary B.C.C. Alloys with Substitutional Disorder, Metallofiz. Noveishie Tekhnol., 37, No. 10: 1405—1424 (2015) (in Russian)