The effects of adding elements of the same group on the magnetic properties of FeP amorphous alloys

Abstract

Although relevant theories and models have been used in certain studies on the magnetic properties of amorphous alloys, the influence mechanism of metalloid elements on the magnetic properties of amorphous alloys is currently unclear. The effects of adding the same group of metalloid elements, C, Si, and Ge, on the magnetic properties of FeP amorphous alloys were systematically investigated by utilizing first-principle molecular dynamics. With the replacement of P atoms by C, Si, and Ge, the magnetic moments of the three types of amorphous alloys increase, and the results of the theoretical simulation are in line with the trend of the experimental results. The study revealed that when smaller-radius C atoms replace larger-radius P atoms, these C atoms tend to fill the gap positions of amorphous alloys so that the number of Fe atoms around the Fe atoms gradually increases, which induces an increase in the magnetic moment of the Fe atoms and ultimately leads to an increase in the magnetic moment of the C_x (x = 5, 10 and 15) amorphous alloys. Nevertheless, when the P atoms are substituted by Si or Ge atoms, their atomic radii are comparable to those of the other atoms. The original positions where the P atoms are located are replaced by Si or Ge atoms, which increases the volume of the amorphous alloy, thereby increasing the distance between the Fe atoms and resulting in a gradual increase in the magnetic moment of the Si_x and Ge_x (x = 5, 10, and 15) amorphous alloys. Additionally, compared with C atoms, when Si or Ge with an atomic radius not much different from that of P is used for replacement, more regular icosahedral distributions appear, which enhances the symmetry of the local atomic structure. This may be one of the reasons why the magnetic moment of Si_x or Ge_x amorphous alloys is greater than that of C_x amorphous alloys.