Structural phase diagram and magnetic properties of Sc-substituted rare earth ferrites R1-xScxFeO3 (R=Lu, Yb, Er, and Ho)

We have studied the structural stability of Sc-substituted rare earth (R) ferrites R1-xScxFeO3 and constructed a structural phase diagram for different R and x. While RFeO3 and ScFeO3 adopt the orthorhombic and bixbyite structure, respectively, the substituted compound R1-xScxFeO3 may be stable in a different structure. Specifically, for R0.5Sc0.5FeO3, the hexagonal structure can be stable for small R, such as Lu and Yb, while the garnet structure is stable for larger R, such as Er and Ho. The formation of the garnet structure of R0.5Sc0.5FeO3 compounds, which requires that Sc occupies both the rare earth and the Fe sites, is corroborated by their magnetic properties.