You are asked to synthesize two samples of La 0.8 Sr 0.2 MnO 3+ , with

You are asked to synthesize two samples of La_0.8Sr_0.2MnO_3+δ, with δ = 0.1 and 0. At which temperature would you equilibrate the δ = 0.1 composition in ambient O₂ atmosphere prior to quenching? How would you equilibrate the δ = 0 composition in commercial Ar gas of p_O2 ≈ 10⁻⁴ bar? Use the Schottky plot in Box 11.2, where isotherms are spaced evenly by 100 degrees.

Schottky plot

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in Lao.8Sr0.2 MnO3+5 0.0 -0.1 -0.2 -0.3 intrinsic Schottky disorder 1000 C -10 500 C log Po (bar) 0