Magnetic moment and exchange interaction in Ni-Gd single and amorphous alloy by MCD and MCP

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The main aim of this project was to reconsider experimentally the famous and well-known "charge transfer model" in Rare Earth(RE)-Transition metal(TM) systems where the outer shell electrons of RE transfer to the 3d band of TM and the magnetic moment of TM decreases gradually with the increase of RE contents. As one of the representation of charge transfer model, we have selected the GdNi_2 Laves phase where the Ni magnetic moment becomes zero because of the filling of Ni 3d band from the outer shell electrons of RE. In addition, the behaviors of magnetic electrons in RE-TM systems such as 3d,4f,5d,6s were investigated in terms of the magnetic moment and exchange interactions J_<ij> which reflect directly the behaviors of magnetic electrons in RE-TM alloys.In order to confirm directly whether the 3d band of Ni is filled or not, the soft X-ray magnetic circular dichroism (MCD) is a powerful tool and the MCD gives other informations such as the ratio of 5pm magnetic moment to angular mom … More entum contribution and the magnetic structure of the sample. Furthermore the magnetic Compton profile (MCP) can give some useful informations regarding the magnetic moment of the consitituents and the magnetic structure. From the macroscopic point of view, the molecular field analysis of the temperature dependence of magnetization of the sample is useful to provide us three exchange interaction constants Jij which include the behaviors of the magnetic electrons in the RE-TM systems.The soft X-ray MCD measument reveals that(1)the 3d band of Ni is not filled in GdNi_2 and also in GdNi(2)the Ni magnetic moment stemming from 3d electrons does exist in GdNi_2 and GdNi and couples antiparallel to that of Gd which is the general rule for the TM-heavy RE including Gd.(3)the magnetic moment due to orbital angular momentum contribution is relatively larger than that of Ni metal.The MCP shows clearly that the Ni retains a magnetic moment in GdNi_2 and couples antiparallel to that of Gd. In addition, the molecular field analysis succseeds in deriving out three exchange interaction constants and explains the Curie Weiss-like behavior of inverse susceptibility based on the ferrimagnetism. Less