Ferromagnetic Properties of Dilute Metal Alloys

Abstract

Several magnetic characteristics of dilute metal alloys are presented in this work. The alloys studied are composed of a paramagnetic host (Pd or Pt) and a ferromagnetic impurity (Fe, Co or Mn) (Mn was also used as a ferromagnetic impurity, since it behaves as such in dilute alloys). The impurity polarizes the surrounding matrix forming giant magnetization clouds that interact with each other producing the onset of ferromagnetism in the whole alloy. The characteristics of these clouds and of the resulting ferromagnetism have been studied by several methods such as magnetization, neutron scattering, etc. In this work, we study how are the magnetization clouds produced, how large are them and what kind of interactions are present, how the phase transition from paramagnetism to ferromagnetism occurs, what are the critical temperatures of these alloys, what type of information can be obtained with neutron scattering on this matter and how is this information affected by critical scattering. To help us investigate these alloys we use a magnetic environment model that, with very few assumptions, can yield the characteristics mentioned, obtaining an excellent comparison with experimental results. We review our results on PdFe, PtCo and PtFe alloys. We also show the results of our latest studies on PdCo and PdMn alloys.