  Functional oxides based resistive memories are recognized as potential
candidate for the next-generation high density data storage and neuromorphic
applications. Fundamental understanding of the compositional changes in the
functional oxides is required to tune the resistive switching characteristics
for enhanced memory performance. Herein, we present the micro/nano-structural
and compositional changes induced in a resistive oxide memory during resistive
switching. Oxygen deficient amorphous chromium doped strontium titanate
(Cr:$a$-SrTiO$_{3-x}$) based resistance change memories are fabricated in a
Ti/Cr:$a$-SrTiO$_{3-x}$ heterostructure and subjected to different biasing
conditions to set memory states. Transmission electron microscope based
cross-sectional analyses of the memory devices in different memory states shows
that the micro/nano-structural changes in amorphous complex oxide and
associated redox processes define the resistive switching behavior. These
experimental results provide insights and supporting material for Ref. [1].
