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.

Domain Dynamics of C-Axis Polarization in Bismuth Titanate Crystals

2007 ◽  
Vol 350 ◽  
pp. 69-72 ◽  
Author(s):  
Yuuki Kitanaka ◽  
Yuji Noguchi ◽  
Masaru Miyayama
Keyword(s):  
Electric Field ◽  
Remanent Polarization ◽  
Bismuth Titanate ◽  
Domain Walls ◽  
Polarization Switching ◽  
Optical Microscope ◽  
Saturated Polarization ◽  
Domain State ◽  
Initial Nucleus ◽  
Domain Dynamics

Polarization switching and domain dynamics in unpoled and poled crystals of bismuth titanate by applying electric field along the crystallographic c axis were investigated through polarization measurements and domain observations by optical microscope and piezoelectric force microscope. Poled crystals showed a well-saturated polarization hysteresis with a remanent polarization of 4.4 μC/cm2 and a coercive field of 4.7 kV/cm. Domain observations reveal that lenticular domain acts as an initial nucleus during polarization switching. The sidewise motion of the lenticular-domain walls and resultant single domain state were easily established for the poled crystals, while the lenticular domains observed in unpoled crystals were clamped even though a high electric field was applied to them.

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 The modified magnetodielectric response in KNN-CZFMO based particulate multiferroic composite system

2020 ◽  
Vol 10 (05) ◽  
pp. 2050024 ◽  
Author(s):  
Kulwinder Kaur ◽  
Mandeep Singh ◽  
Jaspal Singh ◽  
Sanjeev Kumar
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Room Temperature ◽  
Research Work ◽  
Hysteresis Loops ◽  
Magnetic Ordering ◽  
X Ray Diffraction ◽  
Universal Power Law ◽  
Multiferroic Composite ◽  
Magnetic Dielectric

Lead-free multiferroic composites of 1[Formula: see text](K[Formula: see text]Na[Formula: see text]NbO[Formula: see text](Co[Formula: see text]Zn[Formula: see text](Fe[Formula: see text]Mn[Formula: see text]O4 (KNN-CZFMO), where [Formula: see text]= 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1.0, have been investigated for their structural, morphological, electrical, magnetic, dielectric and magneto-dielectric properties. Presence of KNN and CZFMO crystal structure in each composite has been confirmed from X-ray diffraction analysis (XRD). Cuboidal-shaped grains of KNN and spherical-shaped grains of CZFMO have been observed by scanning electron microscopy (SEM). The room temperature ferroelectric behavior as confirmed by polarization versus electric field ([Formula: see text]–[Formula: see text] hysteresis loops has been found to be decreasing with increasing CZFMO concentration. Increasing magnetic ordering with the increase in CZFMO concentration in the prepared composites has been observed by magnetization versus magnetic field ([Formula: see text]–[Formula: see text] hysteresis loops. The electrical conductivity of composites has been studied using Jonscher’s universal power law. The room temperature dielectric constant ([Formula: see text] and dielectric loss (tan [Formula: see text] have been observed to decrease with the increase in the frequency of the applied external electric field. The dielectric relaxation behavior has been observed using curve fitting analysis via the Havriliak–Negami relaxation model. Maximum value of the magnetodielectric (MD) effect [Formula: see text]−11% at a frequency of 1 kHz with the applied magnetic field of 1 T has been achieved for 0.9 KNN−0.1 CZFMO ([Formula: see text]= 0.1) composite in the present research work.

Field-induced phase transition and its impact on the magnetoelectric effect in P(VDF-HFP)/Metglas laminates

2009 ◽  
Vol 1199 ◽  
Author(s):  
David Sheng-Guo Lu ◽  
Xin Zhou ◽  
Zhao Fang ◽  
Qiming Zhang
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
Room Temperature ◽  
Remanent Polarization ◽  
Magnetoelectric Effect ◽  
Vinylidene Fluoride ◽  
Bias Field ◽  
Magnetic Bias ◽  
Field Range ◽  
Poly Vinylidene Fluoride

AbstractThe field-induced phase transition driven by electric field was observed in poly(vinylidene fluoride – hexafluoropropylene) (P(VDF-HFP)) 90/10 wt% copolymers. Experimental results indicated that the electric field may remarkably affect the remanent polarization in terms of changing the D-E loop forms from double loops to single loop, starting from 68 MV/m, and completing at 216 MV/m. It was found that the remanent polarization as well as the piezoelectric constant d31 had a linear relationship with the poling electric field in above electric field range. Thus the magnetoelectric (ME) coupling coefficient ME in P(VDF-HFP)/Metglas laminates increased with the poling electric field. Moreover, the cyclic poled ME device demonstrated different peak d.c. magnetic bias field HDC on the ME - HDC curves from conventional room temperature poled ones. The peak ME coefficient obtained was 4 V/cm Oe.

Dielectric Behavior of YMnO3 Epitaxial Thin Film at around Magnetic Phase Transition Temperature

2010 ◽  
Vol 67 ◽  
pp. 176-181
Author(s):  
Kazuhiro Maeda ◽  
Takeshi Yoshimura ◽  
Atsushi Ashida ◽  
Norifumi Fujimura
Keyword(s):  
Thin Film ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Magnetic Ordering ◽  
Polarization Switching ◽  
Dielectric Behavior ◽  
Switching Behavior ◽  
Ferroelectric Polarization ◽  
Nucleation Density ◽  
Epitaxial Thin Film

Relationship between magnetic ordering and ferroelectric polarization switching in YMnO3 epitaxial thin film was investigated. It was found that Néel point of the YMnO3 film is below 80 K, which is consistent with that of YMnO3 single crystal by neutron diffraction. From temperature dependence of the polarization-electric field hysteresis loops and the dielectric permittivity-voltage characteristics, ferroelectric polarization switching behavior was investigated from 300 to 10 K in detail. The ferroelectric polarization switching behavior accords with Ishibashi-Orihara’s theory. Moreover, it was found that the dielectric permittivity under bias electric field have a anomaly below 80 K and the nucleation density for the ferroelectric polarization switching decreases below 130 K, which is higher than 80K.

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.

scholarly journals Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽  
2020 ◽  
Vol 9 (14) ◽  
pp. 4233-4252
Author(s):  
Yael Gutiérrez ◽  
Pablo García-Fernández ◽  
Javier Junquera ◽  
April S. Brown ◽  
Fernando Moreno ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Phase Change Materials ◽  
Two Dimensional ◽  
Active Materials ◽  
Promising Candidate ◽  
Plasmonic Structures ◽  
Resonance Tuning ◽  
The Many ◽  
Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

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