scholarly journals Giant tuning of ferroelectricity in single crystals by thickness engineering

2020 ◽  
Vol 6 (42) ◽  
pp. eabc7156
Author(s):  
Zibin Chen ◽  
Fei Li ◽  
Qianwei Huang ◽  
Fei Liu ◽  
Feifei Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Single Crystals ◽  
Domain Switching ◽  
Ferroelectric Properties ◽  
Strain Engineering ◽  
Sample Thickness ◽  
Surface Strain ◽  
Switching Behavior ◽  
Thickness Effect

Thickness effect and mechanical tuning behavior such as strain engineering in thin-film ferroelectrics have been extensively studied and widely used to tailor the ferroelectric properties. However, this is never the case in freestanding single crystals, and conclusions from thin films cannot be duplicated because of the differences in the nature and boundary conditions of the thin-film and freestanding single-crystal ferroelectrics. Here, using in situ biasing transmission electron microscopy, we studied the thickness-dependent domain switching behavior and predicted the trend of ferroelectricity in nanoscale materials induced by surface strain. We discovered that sample thickness plays a critical role in tailoring the domain switching behavior and ferroelectric properties of single-crystal ferroelectrics, arising from the huge surface strain and the resulting surface reconstruction. Our results provide important insights in tuning polarization/domain of single-crystal ferroelectric via sample thickness engineering.

Characterisation of Thin Film and Single-Crystal CVD Diamond by Absorption and Luminescence Spectroscopy

1989 ◽  
Vol 162 ◽  
Author(s):  
A. T. Collins ◽  
M. Kamo ◽  
Y. Sato
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Radiation Damage ◽  
Single Crystals ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Cvd Diamond ◽  
Luminescence Spectroscopy ◽  
Cathodoluminescence Spectroscopy

ABSTRACTPolycrystalline films and single crystals of diamond produced by microwaveassisted chemical vapour deposition (CVD) have been examined using absorption and cathodoluminescence spectroscopy. Measurements have been carried out on material as-grown, and after radiation damage by 2 MeV electrons.

scholarly journals Broadband Corbino spectroscopy and stripline resonators to study the microwave properties of superconductors

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (3) ◽  
pp. 47 ◽  
Author(s):  
Marc Scheffler ◽  
M. Maximilian Felger ◽  
Markus Thiemann ◽  
Daniel Hafner ◽  
Katrin Schlegel ◽  
...  
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Single Crystals ◽  
Material Properties ◽  
Heavy Fermion ◽  
Low Loss ◽  
Resonant Frequencies ◽  
Microwave Frequencies ◽  
Fundamental Understanding ◽  
Properties Of Superconductors

<p>Superconducting materials are of great interest both for the fundamental understanding of electrons in solids as well as for a range of different applications. Studying superconductors with microwaves offers a direct experimental access to the electrodynamic response of these materials, which in turn can reveal fundamental material properties such as the superconducting penetration depth. Here we describe two different techniques to study superconductors at microwave frequencies: the broadband Corbino approach can cover frequencies from the MHz range up to 50 GHz continuously but is limited to thin-film samples whereas the stripline resonators are sensitive enough to study low-loss single crystals but reveal data only at a set of roughly equidistant resonant frequencies. We document the applicability of these two techniques with data taken on an ultrathin TaN film and a single crystal of the heavy-fermion superconductor CeCu<sub>2</sub>Si<sub>2</sub>, respectively.</p>

Thin Film Capacitors Cut from Single Crystals Using Focused Ion Beam Milling

2002 ◽  
Vol 748 ◽  
Author(s):  
M. M. Saad ◽  
N. J. Donnelly ◽  
R. M. Bowman ◽  
J. M. Gregg
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Single Crystals ◽  
Focused Ion Beam ◽  
Film Growth ◽  
Ion Beam ◽  
Negative Influence ◽  
Cross Sectional ◽  
Thin Film Capacitors ◽  
In Series

ABSTRACTThe Focused Ion Beam Microscope (FIB) has been used to fabricate capacitors from single crystals of BaTiO3 and SrTiO3 with electrode areas ∼200μm2, and thickness of single crystal dielectric between 2μm and 500nm. Cross-sectional transmission electron microscopy revealed that during capacitor fabrication, the FIB rendered around 20nm of dielectric at the electrode-dielectric interface amorphous, associated with local gallium impregnation. Such a region would act electrically in series with the single crystal and would presumably have a considerable negative influence on dielectric properties. However, annealing prior to electrode deposition was found to fully recover the single crystal, and homogenise the gallium profile. Some subsequent dielectric testing of SrTiO3 was performed yielding a room temperature dielectric constant of ∼150 and loss tangent of 0.015 at 100kHz. A technique has therefore been demonstrated which allows fabrication of capacitors in which size-effects in ‘thin-films’ can be studied, without the influence of grain boundaries, and other issues associated with conventional thin film growth.

Nanoscale Ferroelectric Properties of PZN-PT Single Crystals Studied by Scanning Force Microscopy

2003 ◽  
Vol 785 ◽  
Author(s):  
I. K. Bdikin ◽  
V. V. Shvartsman ◽  
A. L. Kholkin
Keyword(s):  
Single Crystals ◽  
Ferroelectric Properties ◽  
Polarization State ◽  
Domain Wall Motion ◽  
Piezoresponse Force Microscopy ◽  
Scanning Force Microscopy ◽  
Switching Behavior ◽  
Zero Field ◽  
Irregular Domain ◽  
Force Microscopy

ABSTRACTHigh-resolution domain studies were performed in Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 (PZN-PT) single crystals via piezoresponse force microscopy (PFM). Irregular domain patterns with the typical sizes of 20–100 nm were observed on the (001)-oriented surfaces of unpoled samples. On the contrary, (111) crystal cuts exhibited normal micron-sized regular domains with the domain boundaries directed along allowed crystallographic planes. The existence of nanodomains in (100)-oriented crystals was tentatively attributed to the relaxor nature of PZN-PT where small polar clusters were predicted to exist upon zero-field cooling. These nanodomains were considered as the nuclei of the opposite polarization state that ease the switching process for this particular crystal cut. Local piezoelectric hysteresis was also performed by PFM on the nanometer scale. Similar switching behavior of (111)- and (100)-oriented PZN-PT crystals suggests that their superior piezoelectric properties can be related to the domain wall motion rather than to the perovskite lattice itself.

Structural and Ferroelectric Properties of Large c/a Phase Bismuth Ferrite Thin Films Prepared by Ion Beam Sputtering

2011 ◽  
Vol 1292 ◽  
Author(s):  
Seiji Nakashima ◽  
Yosuke Tsujita ◽  
Hironori Fujisawa ◽  
Jung Min Park ◽  
Takeshi Kanashima ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Domain Switching ◽  
Ion Beam ◽  
Ferroelectric Properties ◽  
Mixed Phase ◽  
Ion Beam Sputtering ◽  
Beam Sputtering

ABSTRACTBiFeO3 (BFO) thin films have been deposited on SrRuO3/SrTiO3 (001) substrate by using ion beam sputtering process. At low oxygen partial pressure of 11 m Pa, rhombohedral and large c/a mixed phase thin film have been obtained in spite of rhombohedral BFO single phase formation at high oxygen partial pressure of 73 mPa. From wide area 2θ-Ψ mappings, diffraction peaks from large c/a phase BFO thin film were obtained with the same extinction rule as those of rhombohedral BFO. Reciprocal space mappings around BFO (003) and BFO (103) spots indicate that lattice parameters of large c/a phase BFO were a = 0.381 nm and c = 0.461 nm (c/a =1.22), respectively. Moreover ferroelectric domain switching could be observed in both of rhombohedral BFO and mixed phase BFO thin films.

Characterization of Epitaxial Bi-Layer-Structured Bi5Ti3FeO15 (m = 4) and Bi4Ti3O12-Bi5Ti3FeO15 (m = 3-4) Natural-Superlattice-Structured Multiferroic Thin Films Prepared by Pulsed Laser deposition

2007 ◽  
Vol 1034 ◽  
Author(s):  
Seiji Nakashima ◽  
Yoshitaka Nakamura ◽  
Masanori Okuyama
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Pulsed Laser Deposition ◽  
Single Crystals ◽  
Ferroelectric Properties ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Laser Deposition ◽  
Natural Superlattice ◽  
La Doped

AbstractBi-layer-structured mutiferroic Bi5Ti3FeO15 (BTFO15) (m = 4) and natural-superlattice-structured Bi4Ti3O12- Bi5Ti3FeO15 (BIT-BTFO15) (m = 3-4) thin films have been prepared on (001) and (110) oriented SrTiO3 (STO) single crystal substrates by using pulsed laser deposition. X-ray diffraction patterns of these thin films on (00l) STO single crystals shows the obtained thin films were (00l)-oriented layer-perovskite single phase, and BIT-BTFO15 (m = 3-4) natural-superlattice-structure has also obtained. On (110) STO single crystal, layer perovskite (11l) oriented thin films have been also obtained. For characterizing ferroelectric properties, these thin films have been prepared on (001) and (110) oriented La-doped (3.73 wt%) STO single crystal substrates. From ferroelectric D-E hysteresis loops measurements, BTFO15 (m = 4) and BIT-BTFO (m = 3-4) thin films on (110) La-doped STO single crystals shows good ferroelectric hysteresis loops and their double remanent polarizations (2Pr) were 47 μC/cm2 and 44 μC/cm2, respectively. However, these thin films on (001) La-doped STO single crystals do not show ferroelectric characteristics.

Raman Scattering in LiCoO2 Single Crystals and Thin Films

1997 ◽  
Vol 496 ◽  
Author(s):  
J. D. Perkins ◽  
M. L. Fu ◽  
D. M. Trickett ◽  
J. M. McGraw ◽  
T. F. Ciszek ◽  
...  
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Thin Films ◽  
Raman Scattering ◽  
Single Crystal ◽  
Single Crystals ◽  
Phonon Modes ◽  
Al Substitution ◽  
Scattering Measurements ◽  
Oriented Polycrystalline

ABSTRACTWe report Raman scattering measurements for uniaxially textured and randomly oriented polycrystalline LiCoO2 min films as well as for LiCoO2 and LiCo0.4Al0.6O2 single crystals. For both the crystalline LiCoO2 thin film samples and the single crystal LiCoO2 samples, well defined phonon modes are observed at Raman shifts of 486 cm−1 and 596 cm−1corresponding to the expected Eg and Alg modes of the layered LiCoO2 crystal structure with R3m symmetry. Upon Al substitution for Co in LiCoO2, the two phonon modes appear to shift to higher energy, but further work is needed to clarify this point.

scholarly journals Effect of mechanical stresses on the domain structure of barium titanate single crystals

2020 ◽  
Vol 8 (4) ◽  
pp. 66-78
Author(s):  
V. V. Borodina ◽  
S. O. Kramarov
Keyword(s):  
Barium Titanate ◽  
Single Crystals ◽  
Domain Structure ◽  
Oxygen Vacancies ◽  
Domain Walls ◽  
Domain Switching ◽  
Mechanical Load ◽  
Ferroelectric Properties ◽  
Mechanical Stresses ◽  
The Impact

This review article summarizes the material of years of research on the impact of mechanical stresses on the domain structure of multiaxhetoelectrics using the example of barium titanium monocrystals. Since the discovery of the ferroelectric properties of barium titanate in 1944, this material has been the subject of comprehensive investigation as the first practically important and perhaps the most famous ferroelectric. The domain structure of barium titanate is sensitive to mechanical stresses arising both from simple uniaxial compression and from point impacts by local mechanical loading. Mechanical stress applied to a ferroelectric crystal may have a significant effect on dielectric and piezoelectric properties. In particular, 90-degree domain switching is possible under the influence of stresses. The most interesting experimental results are obtained in the study of elastoplastic processes in BaTiO 3 originating from local mechanical stresses. The following features are found and studied: development of strained region around the point of application of the load; “internal” 90-degree domain that does not extend to the crystal surfaces and does not close upon other domains; the growth of 90-degree domains under the influence of residual mechanical stresses; growth of cracks along charged 90-degree domain walls. The notions of “ferroplastic effect” (crystal deformation due to the formation of 90-degree ferroelectric domains) and “ferromechanical effect” (crack formation and growth along charged 90-degree domain walls) are introduced. The hypothesis of a significant role of oxygen vacancies in the processes of 90-degree domain reorientation was put forward and experimentally confirmed. In particular, an increase in the concentration of oxygen vacancies by reducing annealing of barium titanate single crystals creates more favorable conditions for the appearance of an "internal" 90-degree domain under local mechanical load. The study of the mechanisms governing the formation of a domain structure in ferroelectric crystals remains an important problem of modern materials science.

Physical properties of a transition metal oxide: optical and photoelectric properties of single crystal and thin film molybdenum trioxide

1968 ◽  
Vol 304 (1477) ◽  
pp. 211-231 ◽  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Single Crystal ◽  
Single Crystals ◽  
Molybdenum Trioxide ◽  
Polarized Light ◽  
Film Surface ◽  
Activation Energies ◽  
Temperature Range ◽  
Photoelectric Properties

The optical absorption spectra of single crystals and thin films of MoO 3 have been measured in the temperature range 150 to 340 °K with polarized light. At room temperature, the absorption spectrum of a single crystal consists of two peaks at λ 4130 and λ 3930 Å with E || C and only one absorption peak at 4250 Å with E ⊥ C followed by a rapid rise in absorption. The temperature and frequency dependence of the absorption coefficient in the edge over a range of absorption magnitudes 10 2 -10 5 cm -1 are described by expressions of the form K(v, T) = K 0 exp[— (β/kT) (E 0 — hv )]. The temperature dependence of the absorption edge was found to be linear from 340 to 150 °K with a temperature coefficient of — 6.2 x 10 -4 and — 9.3 x 10 -4 eV/°K for E || C and E ⊥ C , respectively. The corresponding temperature co­efficients in thin films are — 2.7 x 10 -4 and —4.0 x 10 -4 eV/°K for E|| and ⊥ to the film surface, respectively. Measurements have been made of the refractive indices of a single crystal and thin films. Ultraviolet irradiation of a thin film of MoO 3 produces a broad colour centre band having a maximum at 8700 Å. Several absorption peaks are resolvable in polarized light. On cooling down to 150 °K, the peak position shifts to shorter wavelength by 400 Å (4.67 x 10 -4 eV/°K). An e. s. r. signal with g = 2.001 ± 0.005 has been observed in the colour film. The electrical conductivity has been measured on single crystals and polycrystalline samples in the temperature range 25 to 500 °C, and the activation energies are found to be 1.83 ± 0.01 eV (intrinsic) and 0.29 to 0.70 eV (extrinsic). Photoconductivity has been measured in single crystals and thin films as a function of photon energy, temperature, and irradiation intensity. Trapping plays a significant role in the conduction phenomena. The thermal activation energies associated with different trapping levels were determined from the photoconductive decay curves and the electrical glow peaks measurements and were found to be in the range 0.16 to 0.64 eV.

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