Compton study of Ni{sub 75}Cu{sub 25} and Ni{sub 75}Co{sub 25} disordered alloys: Theory and experiment
- Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States)
- Faculty of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, al.Mickiewicza 30, 30059 Krakow (Poland)
- Institute of Physics, Warsaw University Branch in Bialystok, Lipowa 41 (Poland)
- Institute of Nuclear Physics, Cracow, Radzikowskiego 152 (Poland)
We present first-principles computations of ferromagnetic electronic structures and spin-resolved Compton profiles along the three high-symmetry directions in Ni{sub 75}Cu{sub 25} and Ni{sub 75}Co{sub 25} disordered alloys, together with the corresponding Compton measurements from single-crystal specimens with a {sup 137}Cs source. The theoretical results are based on the use of the charge- and spin-self-consistent Korringa-Kohn-Rostoker coherent-potential-approximation framework to treat disorder, and the local spin-density scheme for incorporating exchange-correlation effects; the lattice constants in all cases are obtained by minimizing the total energy. The majority-spin spectrum of Ni undergoes relatively small changes upon alloying with Cu or Co, and the associated majority-spin contribution to the Compton profiles of Ni, Ni{sub 75}Cu{sub 25} and Ni{sub 75}Co{sub 25} is nearly the same. In comparing theory and experiment, we focus on anisotropies in Compton profiles, and find the overall agreement with respect to the J{sub 111}{minus}J{sub 100}, J{sub 111}{minus}J{sub 110}, and J{sub 110}{minus}J{sub 100} anisotropies in Ni{sub 75}Cu{sub 25} as well as Ni{sub 75}Co{sub 25} to be reasonable, although some significant discrepancies around p{sub z}=0 are notable. We show clearly that the momentum resolution of 0.4 a.u. (full width at half maximum) of the present experiment washes out some of the fine structure in the Compton spectra, and that these spectral features should be accessible via higher resolution measurements with a synchrotron light source. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 565881
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 57, Issue 1; Other Information: PBD: Jan 1998
- Country of Publication:
- United States
- Language:
- English
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