Effects of annealing process on asymmetric coercivities of Mn-doped BiFeO3 thin films

Thickness effects of Bi0.89Ti0.11FeO3 thin films deposited on PbZr0.2Ti0.79Nb0.01O3 buffer layers

“…It is worth noting that the P r for the films also show weak dependent on the film thickness, the values are in the range of 45-50 C/cm 2 , which are much larger than those of the BFO/Pub(Zr 0.5 Ti 0.5 )O 3 (11.9 C/cm 2 ), Now we discuss the asymmetric coercive fields of the asymmetric Bi 0.89 Ti 0.11 FeO 3 /PZTN bi-layered structures. Generally, the asymmetric coercivities can be frequently observed in BFO-based thin films prepared using the pulsed laser deposition (PLD) technique and metal organic decomposition (MOD) method [10,18,19]. Our recent work demonstrated that the asymmetric coercive fields are related to the preferential polarization direction formed in the BFO-based films [19].…”

Comparative study of Mn3+ and Mn2+ doping effects on structure and electrical properties of BiFeO3 thin films

“…This is because valence states of Fe ions and their percentages are closely connected to the oxygen vacancy amounts caused by a charge compensation effect, which can form to be ðV O 2 À Þ :: ÀðFe 2 þ Fe 3 þ Þ 0 and play an important role in electrical properties of films [19]. Accordingly, it is very necessary to study the narrow-scan XPS spectra of Fe 2p to get the valence information for further electrical properties analysis.…”

Enhanced ferroelectric properties in BiFe0.95Mn0.05O3 thin films

“…Note that the BFMO films in this work were annealed in N 2 at 525 • C that was much lower than the Curie temperature of BFO (850 • C). Therefore, aging can inevitably occur because of the formation of defect complexes between (V O 2− )•• and (A 2+ Fe 3+ ) [15,16]. The polarization (P D ) of defect complexes can align along the direction of P S during aging [21], which in turn provides a driving force to hinder the switching of ferroelectric domains and eventually reverse as-switched domains to their original orientations (i.e., domain backswitching) [16].…”

“…Therefore, aging can inevitably occur because of the formation of defect complexes between (V O 2− )•• and (A 2+ Fe 3+ ) [15,16]. The polarization (P D ) of defect complexes can align along the direction of P S during aging [21], which in turn provides a driving force to hinder the switching of ferroelectric domains and eventually reverse as-switched domains to their original orientations (i.e., domain backswitching) [16]. Therefore, the larger P r value of BFMO 10 min film than that of BFMO 2 min film should be due to the less defect complexes formed during the annealing treatment, which should result from the less (V O 2− )•• because of the smaller volume fraction of grain boundaries.…”

“…Unfortunately, the reported Mn-doped BFO films exhibit a large coercive field (E c > 300 kV/cm) [13,14]. Considering that the BFO-based films may be aged to some extent due to the formation of defect complexes between oxygen vacancies [15,16], it is natural to consider that such a large E c is not an intrinsic characteristic of BFO but should be due to that the ferroelectric domains in the aged films are stabilized by the local field produced by defect complexes. Thus, E c could be reduced to a great extent through decreasing the content of (V O 2− )•• in the film.…”