Effect of external magnetic field on valence-electron structures of Fe and Ni in Invar, Permalloy and the other Fe–Ni alloys by using Kβ-to-Kα X-ray intensity ratios

• The magnetic properties of alloys depend strongly on valence-electron structure.
• n3d and n4s,4p values of alloys depend on external magnetic field.
• The various properties of Fe–Ni alloys can be changed by external magnetic field.
• The present study of Fe–Ni alloys have thrown new light on various application.

The effect of external magnetic field on the valence-electron structures of Fe and Ni in various Fe–Ni alloy compositions was investigated by using X-ray fluorescence spectroscopy. Firstly, Kβ-to-KαKβ-to-Kα X-ray intensity ratios of Fe and Ni in Invar (Fe0.64Ni0.36Fe0.64Ni0.36), Permalloy (Fe0.20Ni0.80Fe0.20Ni0.80) and FexNi1-xFexNi1-x (x=0, 0.40, 0.52, 0.55, 0.61, and 1) alloys were measured without any magnetic field and under 0.5 and 1 T external magnetic fields, separately. Later, the valence-electron structures of Fe and Ni in both pure form and alloys were obtained by comparison of measured X-ray intensity ratios with the results of multi-configurations Dirac-Fock (MCDF) calculations. The results obtained for valence-electron structures of Fe and Ni in various Fe–Ni alloys were evaluated in terms of magnetic field effect, delocalization and/or charge transfer phenomena. The results have shown that valence electron structure of Fe and Ni in Fe–Ni alloys are dependent on both external magnetic field and concentration of alloy elements.