Insight into the intrinsic magnetic properties of dual-main-phase Ce magnets through Ce chemical state

• A series of dual-main-phase Ce magnets were prepared and the intrinsic magnetic property was systematically investigated. • Saturation magnetization increased abnormally in Ce 0.5 due to the decrease of Ce 4+ . • Spin reorientation temperature indicated that Ce substitution for Nd at the 4 f site tends to saturate until at x =0.4-0.5. • Application temperature window was broadened by regulating the spin reorientation temperature. The dual-main-phase (DMP) Ce magnet with isostructural heterogenous Ce-rich and Nd-rich main phase contributes remarkably to balance the utilization of high-abundance rare earths and the performance. The intrinsic magnetic properties and Ce chemical state of DMP magnets are still a gap. In this work, we prepared a series of DMP (Nd 1- x Ce x ) 30 Fe bal Al 0.1 Cu 0.1 B 1 magnets and systematically investigated the intrinsic magnetic properties for the first time through the chemical states of Ce elements. The XRD crystal structure analysis shows that the lattice parameters of the DMP Ce magnets do not vary monotonically with increasing Ce content, which is correlated with the chemical state of the Ce elements and demonstrated by XPS analysis. The results of the thermal expansion properties further demonstrate that the spin reorientation is only a change in the magnetic structure and is not accompanied by a contraction of the lattice. In addition, the application temperature window is broadened by regulating the spin reorientation temperature, contributing to the understanding of the regulation mechanism of the intrinsic magnetic property of DMP Ce magnets.