| We propose a computational materials design of permanent magnets. The Curie temperature of bcc FeV and FeCr alloys with a small content of V or Cr is higher than that of pure bcc Fe, whereas their saturation magnetizations are smaller than that of Fe. Although this has been experimentally known for a long time, not much attention has been paid to it so far and the origin of this increase has not been yet clarified. In the present study, we discuss the origin of the enhancement of magnetism of Fe metal by adding Cr/V on the basis of first-principles electronic structure calculation. The Cr/V d states are located at higher energy region than those of Fe. This causes the d states of Fe next to Cr/V to be pushed down to the lower energy side compared to those of pure Fe due to the hybridization with Cr/V. Thus "mutated" Fe atom enhances the magnetic moment of other Fe atoms as well as the exchange coupling among them. This mechanism is similar to the enhancement of the magnetism in FeCo alloys. Based on this idea, we extend the theory towards designing new type of permanent magnets. |
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