Effect of Zr substitution on the structure and magnetic properties of (Y, Zr) (Fe, Ti)12 compounds

Fe-rich ThMn12-type intermetallic compounds have attracted wide attention due to high potential in advanced permanent magnet motors. However, the necessary addition of the third elements M to stabilize the ThMn12-type structure leads to a substantial decrease of Ms, which becomes a barrier to improve the intrinsic magnetic properties. Some studies showed that substituting Zr for R at the 2a site helped reduce the content of M. In this paper, the effect of Zr substitution on the structure and magnetic properties of (Y, Zr) (Fe, Ti)12 compounds has been investigated utilizing neutron diffraction, magnetic measurement, and first-principles calculation. The results show that Zr substitution obviously enhances the stability and significantly reduces the content of Ti. In Y1-xZrxFe11.5Ti0.5 compounds, the competition between the magnetic volume effect and the chemical bonding effect of Zr leads to a maximum of Ms when Zr = 0.2. In addition, Y0.7Zr0.3(Fe0.75Co0.25)11.7Ti0.3 compound containing the lowest content of Ti is successfully prepared, with Ms and Tc reaching 163.4 Am2/kg (12.26 kG) and 843.4 K, respectively. The highest Ms of 167.7 Am2/kg (12.53 kG) and Tc of 829.6 K are obtained in Y0.7Zr0.3(Fe0.75Co0.25)11.6Ti0.4, which are superior to those of Nd-Fe-B and show great potential for permanent magnet applications.