scholarly journals Indirect but Efficient: Laser-Excited Electrons Can Drive Ultrafast Polarization Switching in Ferroelectric Materials

2019 ◽  
Vol 10 (12) ◽  
pp. 3402-3407 ◽  
Author(s):  
Chao Lian ◽  
Zulfikhar A. Ali ◽  
Hyuna Kwon ◽  
Bryan M. Wong
Keyword(s):  
Polarization Switching ◽  
Ferroelectric Materials

Giant room temperature elastocaloric effect of PbTiO3 ferroelectric materials with 90° domain structure

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 70557-70562 ◽  
Author(s):  
F. Wang ◽  
B. Li ◽  
Y. Ou ◽  
L. F. Liu ◽  
C. Z. Peng ◽  
...  
Keyword(s):  
Stress Field ◽  
Domain Structure ◽  
Applied Stress ◽  
Room Temperature ◽  
Polarization Switching ◽  
Ferroelectric Materials ◽  
Stress Fields ◽  
Elastocaloric Effect

The elastocaloric effect in PbTiO3 with 90° domain structure under the applied stress field at room temperature has been studied. A negative ΔTσ of −7.2 K can be obtained by controlled polarization switching under the applied stress fields.

scholarly journals Reliable polarization switching of BiFeO 3

2012 ◽  
Vol 370 (1977) ◽  
pp. 4872-4889 ◽  
Author(s):  
S. H. Baek ◽  
C. B. Eom
Keyword(s):  
Electric Field ◽  
Room Temperature ◽  
Remanent Polarization ◽  
Magnetic Ordering ◽  
Polarization Switching ◽  
Ferroelectric Materials ◽  
Promising Candidate ◽  
Switching Path ◽  
Ferroelectric Memory ◽  
Rhombohedral Symmetry

As a room temperature multi-ferroic with coexisting anti-ferromagnetic, ferroelectric and ferroelastic orders, BiFeO 3 has been extensively studied to realize magnetoelectric devices that enable manipulation of magnetic ordering by an electric field. Moreover, BiFeO 3 is a promising candidate for ferroelectric memory devices because it has the largest remanent polarization ( P r >100 μC cm −2 ) of all ferroelectric materials. For these applications, controlling polarization switching by an electric field plays a crucial role. However, BiFeO 3 has a complex switching behaviour owing to the rhombohedral symmetry: ferroelastic (71 ° , 109 ° ) and ferroelectric (180 ° ) switching. Furthermore, the polarization is switched through a multi-step process: 180 ° switching occurs through three sequential 71 ° switching steps. By using monodomain BiFeO 3 thin-film heterostructures, we correlated such multi-step switching to the macroscopically observed reliability issues of potential devices such as retention and fatigue. We overcame the retention problem (i.e. elastic back-switching of the 71 ° switched area) using monodomain BiFeO 3 islands. Furthermore, we suppressed the fatigue problem of 180 ° switching, i.e. loss of switchable polarization with switching cycles, using a single 71 ° switching path. Our results provide a framework for exploring a route to reliably control multiple-order parameters coupled to ferroelastic order in other rhombohedral and lower-symmetry materials.

Ferroelectric Materials: Probing Local and Global Ferroelectric Phase Stability and Polarization Switching in Ordered Macroporous PZT (Adv. Funct. Mater. 5/2011)

2011 ◽  
Vol 21 (5) ◽  
pp. 802-802 ◽  
Author(s):  
Martyn A. McLachlan ◽  
David W. McComb ◽  
Mary P. Ryan ◽  
Anna N. Morozovska ◽  
Eugene A. Eliseev ◽  
...  
Keyword(s):  
Phase Stability ◽  
Ferroelectric Phase ◽  
Polarization Switching ◽  
Ferroelectric Materials ◽  
Ordered Macroporous

A Nonlinear Multi-Field Coupling Finite Element Method for Polarization Switching in Ferroelectrics

2008 ◽  
Author(s):  
Jie Wang ◽  
Marc Kamlah
Keyword(s):  
Finite Element ◽  
Virtual Work ◽  
Three Dimensional ◽  
Polarization Switching ◽  
Ferroelectric Materials ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Polarization Distribution ◽  
Field Coupling ◽  
Simulated System

A three-dimensional nonlinear finite element formulation for ferroelectric materials is developed based on a principle of virtual work. The formulation includes the coupling of three physical fields, namely polarization field, electric field and strain field. The developed finite element formulation is employed to investigate the polarization distribution near a flaw in a ferroelectric single crystal under mechanical loadings. It is found that the polarization switching takes place near the flaw tip if the loadings exceed a critical value. In the simulation, we do not take any prior assumptions, i.e. without any switching criterion, on the polarization switching. The polarization switching is a result of the minimization of the total energy in the simulated system.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

Investigation of ferroelectrics using conventional and in situ electron microscopy

1994 ◽  
Vol 52 ◽  
pp. 586-587
Author(s):  
V. Saikumar ◽  
H. M. Chan ◽  
M. P. Harmer
Keyword(s):  
Nonvolatile Memory ◽  
Ferroelectric Materials ◽  
Gate Insulator ◽  
Sensors And Actuators ◽  
In Situ Electron Microscopy ◽  
Ferroelectric Domains ◽  
Domain Boundaries ◽  
Domain Interactions ◽  
Memory Applications

In recent years, there has been a growing interest in the application of ferroelectric thin films for nonvolatile memory applications and as a gate insulator in DRAM structures. In addition, bulk ferroelectric materials are also widely used as components in electronic circuits and find numerous applications in sensors and actuators. To a large extent, the performance of ferroelectric materials are governed by the ferroelectric domains (with dimensions in the micron to sub-micron range) and the switching of domains in the presence of an applied field. Conventional TEM studies of ferroelectric domains structures, in conjunction with in-situ studies of the domain interactions can aid in explaining the behavior of ferroelectric materials, while providing some answers to the mechanisms and processes that influence the performance of ferroelectric materials. A few examples from bulk and thin film ferroelectric materials studied using the TEM are discussed below.Figure 1 shows micrographs of ferroelectric domains obtained from undoped and Fe-doped BaTiO3 single crystals. The domain boundaries have been identified as 90° domains with the boundaries parallel to <011>.

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