Epitaxial ferroelectric one direction over the thin fihns on single-crystal substrates generally show a preferred domain orientation in other in demonstration of a poor polarization retention. This behavior will affec...Epitaxial ferroelectric one direction over the thin fihns on single-crystal substrates generally show a preferred domain orientation in other in demonstration of a poor polarization retention. This behavior will affect their application in nonvolatile ferroelectric random access memories where bipolar polarization states are used to store the logic 0 and 1 data. Here the retention characteristics of BiFe03 thin films with Srftu03 bottom electrodes on both GdSc03 （110） and SrTiO3 （100） substrates are studied and compared, and the results of piezoresponse force microscopy provide a long time retention property of the films on two substrates. It is found that bismuth ferrite thin films grown on GdScO3 substrates show no preferred domain variants in comparison with the preferred downward polarization orientation toward bottom electrodes on SrTi03 substrates. Tile retention test from a positive-up domain to a negative-down domain using a signal generator and an oscilloscope coincidentally shows bistable polarization states on the GdSeOa substrate over a measuring time of 500s, unlike the preferred domain orientation on SrTi03, where more than 65~o of upward domains disappear after 1 s. In addition, different sizes of domains have been written and read by using the scanning tip of piezoresponse force microscopy, where the polarization can stabilize over one month. This study paves one route to improve the polarization retention property through the optimization of the lattice-mismatched stresses between films and substrates.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2014CB921004the National Natural Science Foundation of China under Grant No 61225020
文摘Epitaxial ferroelectric one direction over the thin fihns on single-crystal substrates generally show a preferred domain orientation in other in demonstration of a poor polarization retention. This behavior will affect their application in nonvolatile ferroelectric random access memories where bipolar polarization states are used to store the logic 0 and 1 data. Here the retention characteristics of BiFe03 thin films with Srftu03 bottom electrodes on both GdSc03 （110） and SrTiO3 （100） substrates are studied and compared, and the results of piezoresponse force microscopy provide a long time retention property of the films on two substrates. It is found that bismuth ferrite thin films grown on GdScO3 substrates show no preferred domain variants in comparison with the preferred downward polarization orientation toward bottom electrodes on SrTi03 substrates. Tile retention test from a positive-up domain to a negative-down domain using a signal generator and an oscilloscope coincidentally shows bistable polarization states on the GdSeOa substrate over a measuring time of 500s, unlike the preferred domain orientation on SrTi03, where more than 65~o of upward domains disappear after 1 s. In addition, different sizes of domains have been written and read by using the scanning tip of piezoresponse force microscopy, where the polarization can stabilize over one month. This study paves one route to improve the polarization retention property through the optimization of the lattice-mismatched stresses between films and substrates.
