Room temperature multiferroic properties and polymorphic phase transition-induced noticeable magnetodielectric anomalies in Fe/Co co-doped (K0.52Na0.48)NbO3 ceramics

Doping effect on the lattice parameters, vibration modes, dielectric and piezoelectric properties of LiSbO3, LiTaO3 and LiNbO3 substituted lead-free K0.5Na0.5NbO3 (KNN) ceramics are investigated. All compositions are crystallized in morphotropic phase boundary region. Enhanced piezoelectric and electromechanical response d33 ~176–197 pC/N, kp ~45%–48%, and kt~34%–47% obtained in the doped ceramics are due to the presence of the polymorphic phase transition between orthorhombic and tetragonal phase at room temperature.

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Polymorphic Phase Transition and Piezoelectric Performance of BaTiO3-CaSnO3 Solid Solutions

Actuators ◽

10.3390/act10060129 ◽

2021 ◽

Vol 10 (6) ◽

pp. 129

Author(s):

Qian Wang ◽

Hong-Ze Yan ◽

Xian Zhao ◽

Chun-Ming Wang

Keyword(s):

Phase Transition ◽

Solid Solutions ◽

Room Temperature ◽

Electromechanical Coupling ◽

Piezoelectric Properties ◽

Ferroelectric Properties ◽

Piezoelectric Response ◽

X Ray Diffraction ◽

Polymorphic Phase Transition ◽

Piezoelectric Strain

BaTiO3-based piezoelectric ceramics have attracted considerable attention in recent years due to their tunable phase structures and good piezoelectric properties. In this work, the (1 − x)BaTiO3−xCaSnO3 (0.00 ≤ x ≤ 0.16, abbreviated as BT−xCS) solid solutions, were prepared by traditional solid-state reaction methods. The phase transitions, microstructure, dielectric, piezoelectric, and ferroelectric properties of BT-xCS have been investigated in detail. The coexistence of rhombohedral, orthorhombic, and tetragonal phases near room temperature, i.e., polymorphic phase transition (PPT), has been confirmed by X-ray diffraction and temperature-dependent dielectric measurements in the compositions range of 0.06 ≤ x ≤ 0.10. The multiphase coexistence near room temperature provides more spontaneous polarization vectors and facilitates the process of polarization rotation and extension by an external electric field, which is conducive to the enhancement of piezoelectric response. Remarkably, the composition of BT-0.08CS exhibits optimized piezoelectric properties with a piezoelectric coefficient d33 of 620 pC/N, electromechanical coupling factors kp of 58%, kt of 40%, and a piezoelectric strain coefficient d33* of 950 pm/V.

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Study on Defect Complexes in High-K Sr and Zr Co-Doped BaTiO3 Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.501 ◽

2013 ◽

Vol 750-752 ◽

pp. 501-505

Author(s):

Da Yong Lu ◽

Xiu Yun Sun

Keyword(s):

Crystal Structure ◽

Phase Transition ◽

Diffuse Phase Transition ◽

Room Temperature ◽

Raman Band ◽

Phase Transition Behavior ◽

Defect Complexes ◽

High K ◽

Diffuse Phase ◽

Co Doped

In order to investigate the evidence for the formation of Sr2+-Zr4+ defect complexes in high-k Sr and Zr co-doped BaTiO3 ceramics, BaTiO3, (Ba0.85Sr0.15)TiO3, Ba (Ti0.8Zr0.2)O3, and (Ba0.85Sr0.15)(Ti0.8Zr0.2)O3 (BS15TZ20) ceramics were prepared using a mixed oxide method. The Y5V-type BS15TZ20 shows a high-k diffuse phase transition behavior (ε ́m = 8000) and its Curie peak occurs near room temperature. The evolution in crystal structure and in dielectric property for the four samples gives four evidences for the formation of Sr2+-Zr4+ defect complexes in BS15TZ20. The splitting of the 720 cm-1 Raman band does not relate to Sr2+-Zr4+ defect complexes, but to a multiphonon (A1 (TO2) + A1 (TO3)).

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Dielectric, Piezoelectric, Pyroelectric Properties and Polymorphic Phase Transition of 0.95 (KXNa1-X) NbO3-0.05LiSbO3 Lead-Free Ferroelectric Ceramics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.377.161 ◽

2013 ◽

Vol 377 ◽

pp. 161-165

Author(s):

Yang Yang Zhang ◽

Jin Ping Zhang ◽

Er Ping Wang ◽

Sheng Lin Jiang ◽

Lin Lu

Keyword(s):

Phase Transition ◽

Transition Temperature ◽

Electrical Properties ◽

Room Temperature ◽

Lead Free ◽

Ferroelectric Ceramics ◽

Polymorphic Phase Transition ◽

Lead Free Ceramics ◽

Enhanced Properties ◽

Tetragonal Phase Transition

0.95 (KXNa1-X) NbO3-0.05 LiSbO3(KNN-LS-X) (X=0.4-0.5) lead-free ceramics were prepared by conventional solid method. The effect of K/Na ratio on the dielectric, piezoelectric, pyroelectric and polymorphic phase transition was studied. The results show that the electrical properties strongly depend on the K/Na ratio. The KNN-LS-X(X=0.45) ceramics exhibit enhanced properties (εr=891.267,d33=222pC/N,Kp=0.43517,Qm=64.72,p=15×10-4C/m2K). Enhanced electrical properties of the KNN-LS-X (X=0.45) ceramics could be attributed to the effect of K/Na ratio modifying the polymorphic orthorhombic-tetragonal phase transition temperature to room temperature, which could make KNN-LS-X (X=0.45) ceramics use as a new ferroelectric sensor.

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Phase transition and enhanced multiferroic properties of (Sm, Mn and Cr) co-doped BiFeO3 thin films

Ceramics International ◽

10.1016/j.ceramint.2014.04.058 ◽

2014 ◽

Vol 40 (8) ◽

pp. 12179-12185 ◽

Cited By ~ 20

Author(s):

Wenlong Liu ◽

Guoqiang Tan ◽

Xu Xue ◽

Guohua Dong ◽

Huijun Ren ◽

...

Keyword(s):

Thin Films ◽

Phase Transition ◽

Multiferroic Properties ◽

Bifeo3 Thin Films ◽

Co Doped

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Preparation and investigation of co-doped VO2 powders

Functional Materials Letters ◽

10.1142/s1793604719500152 ◽

2019 ◽

Vol 12 (02) ◽

pp. 1950015 ◽

Cited By ~ 1

Author(s):

Lingna Liu ◽

Yi Hou ◽

Xiuzhao Yin ◽

Fang Zhang ◽

Zifei Peng

Keyword(s):

Phase Transition ◽

Vanadium Dioxide ◽

Room Temperature ◽

Hydrothermal Reaction ◽

Raw Materials ◽

Sodium Molybdate ◽

Tungstic Acid ◽

Ft Ir ◽

Preliminary Study ◽

Co Doped

In this paper, tungsten-and molybdenum-doped vanadium dioxide (VO[Formula: see text] powders were prepared by hydrothermal reaction using vanadium pentoxide (V2O[Formula: see text], H2O2, white tungstic acid (WPTA) and sodium molybdate (Na2MoO[Formula: see text] as raw materials. The microstructure and composition of VO2 powders were characterized by means of XRD, XPS, DSC and FT-IR. We made a preliminary study on the thermal-induced phase transition properties of powders. The experimental results show that the co-doped samples are monoclinic rutile. Tungsten and molybdenum atoms exist in the lattice at the positive six valence. When the W and M W were 3% and 2%, respectively, the transition temperature of co-doped samples were close to room temperature can reach 25.5∘C.

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Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173996 ◽

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.

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Survival of mouse blastocysts after low-temperature preservation under high pressure

Acta Veterinaria Hungarica ◽

10.1556/avet.52.2004.4.10 ◽

2004 ◽

Vol 52 (4) ◽

pp. 479-487 ◽

Cited By ~ 7

Author(s):

Cs. Pribenszky ◽

M. Molnár ◽

S. Cseh ◽

L. Solti

Keyword(s):

Phase Transition ◽

Hydrostatic Pressure ◽

Low Temperature ◽

High Hydrostatic Pressure ◽

Room Temperature ◽

Freezing Point ◽

Significant Loss ◽

Embryo Cryopreservation ◽

Subzero Temperatures ◽

Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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