Enhanced spontaneous polarization in double perovskite Bi2FeCrO6 films |
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| Authors: | Dehuan Meng Yunsheng Xiao Hongcai He Yulong Liao Huaiwu Zhang Junyi Zhai Zuhuang Chen Lane W Martin Feiming Bai |
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| Affiliation: | 1. State Key Laboratory of Electronic Thin films and Integrated Devices, University of Electronic Science and Technology, Chengdu, China;2. CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Science, Beijing, China;3. Department of Materials Science and Engineering, University of California, Berkeley, California
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California |
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| Abstract: | We report the pulsed-laser deposition of epitaxial double-perovskite Bi2FeCrO6 (BFCO) films on the (001)-, (110), and (111)-oriented single-crystal SrTiO3 substrates. All of the BFCO films with various orientations show the  and  superlattice-diffraction peaks. The intensity ratios between the  -superlattice and the main 111-diffraction peak can be tailored by simply adjusting the laser repetition rate and substrate temperature, reaching up to 4.4%. However, both optical absorption spectra and magnetic measurements evidence that the strong superlattice peaks are not correlated with the B-site Fe3+/Cr3+ cation ordering. Instead, the epitaxial (111)-oriented Bi2FeCrO6 films show an enhanced remanent polarization of 92 μC/cm2 at 10 K, much larger than the predicted values by density-functional theory calculations. Positive-up-negative-down (PUND) measurements with a time interval of 10 μs further support these observations. Therefore, our experimental results reveal that the strong superlattice peaks may come from A- or B-site cation shifts along the pseudo-cubic 111] direction, which further enhance the ferroelectric polarization of the BFCO thin films. |
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| Keywords: | anomalous photovoltaic bandgap ferroelectric materials magnetization perovskite oxides |
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