Comparison of the mean sum of particle volume (±s.d.) of STNNi (STNNi bottom ) with a four-monolayer-thick top layer of donor-doped Nb:SrTiO 3 (NbSTO top ) or undoped SrTiO 3 (STO top ; naturally acceptor doped by impurities). After initial thermal oxidation ( p (O 2 ) = 0.108 mbar, T = 400 C, t = 60 min), the samples are thermally reduced (4% H 2 /Ar, T = 600 C, t = 5 h). A clear influence of the redox chemistry of the top layer material on the exsolution response is apparent. The nanoparticle volume is determined based on the topological data, showing averaged values obtained from three 2 × 2 µm 2 scans for each condition.
