Phase Stability, Structural Evolution and Magnetic Properties of Sc(1-x)LuxVO3 (0.0 x 1.0)

We report the synthesis and formation mechanism of Sc (i-x )Lu x VO 3 (0.0 ≤ x ≤ 1.0) using in situ powder X-ray diffraction and bulk solid-state preparation methods. The reduction of the solid solution Sc (i-x )Lu x VO 4 (0.0 ≤ x ≤ 1.0) results in orthorhombic perovskites (space group Pnma) Sc 1-x )Lu x VO 3 for x ≥≥≥≥ 0.58 and cubic bixbyites (space group: Ia3) Sc (1-x )Lu x VO 3 for Sc-rich samples with x < 0.1. During the high-temperature synthesis, Sc-rich bixbyite structures are initially formed and in a second step Lu-rich perovskites are formed. This two-step process is followed by Sc-Lu exchange between the two initial phases as shown by time-resolved powder X-ray diffraction. The in situ diffraction studies provide the basis for the preparation of metastable bixbyite as well as thermodynamically stable perovskite and bixbyite phases. For the perovskite phases, low-temperature powder neutron diffraction data and dc magnetic susceptibility data show that the Neel temperatures for the canted antiferromagnets range from 50 K for x = 0.58 to 100 K for x = 0.9. The Neel temperatures correlate with the V-O-V bond angles in the orthorhombic structures. The magnetic structure evolution has been followed as a function of temperature using powder neutron diffraction. In contrast, the cation-disordered bixbyite phases do not undergo magnetic long-range ordering, even at temperatures as low as 3 K.