TY - JOUR
T1 - Time- and strain-dependent nanoscale structural degradation in phase change epitaxial strontium ferrite films
AU - Wang, Le
AU - Yang, Zhenzhong
AU - Wu, Jinpeng
AU - Bowden, Mark E.
AU - Yang, Wanli
AU - Qiao, Amy
AU - Du, Yingge
N1 - Publisher Copyright:
© 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
PY - 2020/12
Y1 - 2020/12
N2 - Topotactic phase transition between metallic, perovskite SrFeO3 and insulating, Brownmillerite SrFeO2.5 has been extensively studied due to the potential applications in resistive switching devices for neuromorphic computing. However, its practical utilization as memristors has been hindered by the structural instability of SrFeO3, which is often ascribed to the generation of oxygen vacancies to form SrFeO3-δ. Here we reveal that the dominating defects generated in SrFeO3 epitaxial thin films are atomic scale gaps generated as a result of interfacial strain. Our correlated time- and strain-dependent measurements show that tensile strained SrFeO3 films form vertical, nanoscale gaps that are SrO-rich, which are accountable for the observed metal-to-insulator transition over time. On the other hand, compressively strained or small lattice mismatched SrFeO3 films mainly yield horizontal gaps with a smaller impact on the in-plane transport. The atomic scale origin of such defects and their impact on device performance need to be further understood in order to integrate phase change materials in oxide electronics.
AB - Topotactic phase transition between metallic, perovskite SrFeO3 and insulating, Brownmillerite SrFeO2.5 has been extensively studied due to the potential applications in resistive switching devices for neuromorphic computing. However, its practical utilization as memristors has been hindered by the structural instability of SrFeO3, which is often ascribed to the generation of oxygen vacancies to form SrFeO3-δ. Here we reveal that the dominating defects generated in SrFeO3 epitaxial thin films are atomic scale gaps generated as a result of interfacial strain. Our correlated time- and strain-dependent measurements show that tensile strained SrFeO3 films form vertical, nanoscale gaps that are SrO-rich, which are accountable for the observed metal-to-insulator transition over time. On the other hand, compressively strained or small lattice mismatched SrFeO3 films mainly yield horizontal gaps with a smaller impact on the in-plane transport. The atomic scale origin of such defects and their impact on device performance need to be further understood in order to integrate phase change materials in oxide electronics.
UR - https://www.scopus.com/pages/publications/85092930835
U2 - 10.1038/s41529-020-0120-3
DO - 10.1038/s41529-020-0120-3
M3 - 文章
AN - SCOPUS:85092930835
SN - 2397-2106
VL - 4
JO - npj Materials Degradation
JF - npj Materials Degradation
IS - 1
M1 - 16
ER -