Forming a Cr4+(3d2) spin doped Zr1−xCrxO2 (x ≤ 0.2) of small crystallites at moderate pressure: A spin-semiconductor

摘要: Abstract A spin Cr 4+ (3d 2 ) doped ZrO dielectric phase has tailored magnetism, ionic conductivity and optical properties. The synthesis is made with a polymer complex of 6+ Zr salts in glycerol that gives controlled conversion  → Cr ambient air. At ∼320 K open air, CrO 3 solution (orange color) forms metal ion–polymer which darkens to blackish color species. hydrogel dried at ∼330 K heated an autoclave small pressure ∼0.5 bar 420–470 K so it yields 1− x O (  ≤ 0.2) buried carbon burnt out when annealing higher temperatures ≥673 K Small crystallites, D  = 3–10 nm diameter, adapt cubic -type ≤1073 K. As much as 20 mol%  = 0.2) this way. An optimal 773 K  = 5 nm sample plates magnetization M  = 9.08 emu g −1 (in the part) coercivity H c  = 54.2 Oe 295 K, or  = 85.79 emu g  = 100 Oe) 5 K magnetic hysteresis loop (not saturating until 60 kOe field). Curie point ∼482 K enhanced over (387 K) by strong –O 2− –Cr superexchange interaction. Spin-assisted electrical drops largely 85–100%, depending on applied frequency 10–100 kHz, paramagnetic → ferromagnetic order. core–shell crystallites facilitate both transport