Magnetism in an Amorphous Fe-Pd-P Alloy System

• Main Author: Sharon, Thomas Edward
• Format: Others
• Published: 1971
• Online Access: https://thesis.library.caltech.edu/10803/1/Sharon_TE_1971.pdf; Sharon, Thomas Edward (1971) Magnetism in an Amorphous Fe-Pd-P Alloy System. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/SKE6-7667. https://resolver.caltech.edu/CaltechTHESIS:04122018-091817826 <https://resolver.caltech.edu/CaltechTHESIS:04122018-091817826>

<p>Amorphous alloys of composition Fe_xPd_80-xP₂₀ (13 &#8804; x &#8804; 44) have been prepared by rapid quenching from the liquid state. The Mössbauer effect in Fe⁵⁷ has been used to study the magnetic properties of these materials. The hyperfine field distributions have been determined from these experiments, as a function of composition and temperature. The results indicate that the electronic state of Fe in these alloys remains essentially constant throughout the composition range, and that the Pd d band is filled by electron transfer from phosphorus.</p> <p>The variation of the magnetic transition temperature with composition has been determined by combining the Mössbauer effect results with complementary magnetic measurements. There is a sharp change in the slope in this curve at x ≃ 26. Below this concentration, the long range magnetic order which prevails in the higher Fe concentration alloys has broken down, giving rise to a more local ordering.</p> <p>The Mössbauer effect results confirm the existence of weakly coupled Fe atoms in all the amorphous Fe-Pd-P alloys. These atoms reside in low effective fields, and can participate in the spin-flip scattering process which produces a Kondo effect (resistivity minimum). The large critical concentration observed is also an indication that the spin correlations are greatly reduced in these amorphous alloys.</p>