Session:

There is a need to accelerate materials development and discovery, moving away from empirical studies. Towards this goal, a paradigm shift is needed in which computational analysis will play an important role. Here, we use the combination of three highly complementary scientific domains to rationalize Bismuth ferrite (BiFeO3) crystallization pathways: (i) text-mining to extract synthesis recipes from existing literature to guide experiment design, (ii) in situ X-ray scattering (XRD) to follow crystallization pathways to develop a comprehensive understanding of BiFeO₃ thin-film formation using solution processing and the correlation between precursor choice and impurity phase formation, and (iii) ab initio calculations to develop a comprehensive understanding of thin-film formation from fundamental principles and taking into account in situ XRD data. We use the feedback between the three techniques to design efficient experiments, refine our understanding of the BiFeO₃ crystallization pathway, and provide rational guidelines for precise control of BiFeO₃ crystallization.

BiFeO₃ is a multiferroic example material chosen here. It is a lead-free environmentally friendly material for next-generation non-toxic ferroelectric memory and spintronic devices, and a promising replacement for Pb(Zr,Ti)O₃ (PZT). We show how combined text-mining, in situ characterization, and fundamental science modeling help to control the quality and purity of BiFeO₃ thin films. Text-mining findings reveal that the Bi₂Fe₄O₉ impurity phase is the most occurring in literature. This is backed up by thermodynamic calculations which indicate that this impurity phase has the closest formation energy to BiFeO₃ and is therefore the most competing phase. Both text-mining and thermodynamic calculations predict that the formation of impurities is more likely at higher temperatures which was confirmed by in situ XRD. The latter helped to define processing parameters that can allow for a lowering of the annealing temperature such as the use of ethylene glycol or excess-Bi in the precursor. Lastly, in situ XRD results showed the formation of an intermediate Bi₂O₂CO₃ phase which was not reported in the literature before. Thermodynamic calculations revealed that the formation energy of BiFeO₃ is lowered as compared to Bi₂Fe₄O₉ in the presence of this intermediate phase. The tremendous synergy between the scientific domains is exemplified and it is demonstrated how rational guidelines for controlling high-quality and phase pure material synthesis can be developed.

Co-Author(s): Kootak Hong (Lawrence Berkeley National Laboratory), Kevin Cruse (University of California, Berkeley), Christopher Bartel (University of California, Berkeley), Viktoriia Baibakova (University of California, Berkeley), Gerbrand Ceder (University of California, Berkeley), Carolin Sutter-Fella (Lawrence Berkeley National Laboratory)

Maged Abdelsamie

Lawrence Berkeley National Laboratory

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