In-Plane Ferroelectricity in Strontium Titanate Thin Films

2003 ◽  
Vol 783 ◽  
Author(s):  
K. F. Astafiev ◽  
V. O. Sherman ◽  
M. Cantoni ◽  
A. K. Tagantsev ◽  
N. Setter ◽  
...  
Keyword(s):  
Thin Films ◽  
Low Temperatures ◽  
Ferroelectric Phase ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Laser Deposition ◽  
Polarization Response ◽  
Transmission Electron ◽  
The Difference ◽  
Electrical Characterizations

ABSTRACTThe results of structural and electrical characterizations of SrTiO3 thin films deposited onto LaAlO3 substrates by pulsed laser deposition technique are presented. The appearance of the ferroelectric phase in these films has been experimentally documented, the transition temperature being in the range of 90–120K. The hysteresis loops have been monitored in a wide temperature range by using thin film planar capacitors, the driving field being predominantly in the plane of the film. The switching properties of the films has been studied at low temperatures (∼25K) and well saturated loops have been observed with relatively low coercive field (<6kV/cm for 10μm gap). The presence of the imprint phenomenon has been also found at low temperatures.The microstructure of the investigated SrTiO3 thin films has been studied by using a high resolution transmission electron microscope (TEM). It has been found that the annealed and as-deposited thin films, being of the same composition, have quite different microstructures. The difference observed in the polarization response of the films is related to that in their microstructure.

Epitaxial Growth of AlN Thin Films on Silicon and Sapphire by Pulsed Laser Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Vispute ◽  
H. Wu ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Breakdown Field ◽  
Transmission Electron ◽  
Uv Visible ◽  
Relationship Of

ABSTRACTAIN thin films have been grown epitaxially on Si(111) and Al2O3(0001) substrates by pulsed laser deposition. These films were characterized by FTIR and UV-Visible, x-ray diffraction, high resolution transmission electron and scanning electron microscopy, and electrical resistivity. The films deposited on silicon and sapphire at 750-800°C and laser energy density of ∼ 2 to 3J/cm2 are epitaxial with an orientational relationship of AIN[0001]║ Si[111], AIN[2 110]║Si[011] and AlN[0001]║Al2O3[0001], AIN[1 2 1 0]║ Al2O3[0110] and AIN[1010] ║ Al2O3[2110]. The both AIN/Si and AIN/Al2O3 interfaces were found to be quite sharp without any indication of interfacial reactions. The absorption edge measured by UV-Visible spectroscopy for the epitaxial AIN film grown on sapphire was sharp and the band gap was found to be 6.1eV. The electrical resistivity of the films was about 5-6×l013Ω-cm with a breakdown field of 5×106V/cm. We also found that the films deposited at higher laser energy densities ≥10J/cm2 and lower temperatures ≤650°C were nitrogen deficient and containing free metallic aluminum which degrade the microstructural, electrical and optical properties of the AIN films

(111)p microtwinning in SrRuO3 thin films on (001)p LaAlO3

2009 ◽  
Vol 65 (6) ◽  
pp. 694-698 ◽  
Author(s):  
Y. Han ◽  
I. M. Reaney ◽  
D. S. Tinberg ◽  
S. Trolier-McKinstry
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Orientation Relationship ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Zone Axis ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Diffraction Patterns

SrRuO3 (SRO) thin films grown on (001)p (p = pseudocubic) oriented LaAlO3 (LAO) by pulsed laser deposition have been characterized using transmission electron microscopy. Observations along the 〈100〉p directions suggests that although the SRO layer maintains a pseudocube-to-pseudocube orientation relationship with the underlying LAO substrate, it has a ferroelastic domain structure associated with a transformation on cooling to room temperature to an orthorhombic Pbnm phase (a − a − c + Glazer tilt system). In addition, extra diffraction spots located at ±1/6(ooo)p and ±1/3(ooo)p (where `o' indicates an index with an odd number) positions were obtained in 〈110〉p zone-axis diffraction patterns. These were attributed to the existence of high-density twins on {111}p pseudocubic planes within the SrRuO3 films rather than to more conventional mechanisms for the generation of superstructure reflections.

Observation of Large Low Field Magnetoresistance in Ramp-Edge Tunneling Junctions Based on Doped Manganite Ferromagnetic Electrodes and A SrTiO3 Insulator

1997 ◽  
Vol 494 ◽  
Author(s):  
C. Kwon ◽  
Q. X. Jia ◽  
Y. Fan ◽  
M. F. Hundley ◽  
D. W. Reagor ◽  
...  
Keyword(s):  
Thin Films ◽  
Low Temperatures ◽  
Pulsed Laser ◽  
Relative Orientation ◽  
Laser Deposition ◽  
Multilayer Thin Films ◽  
Ion Milling ◽  
Edge Geometry ◽  
Ferromagnetic Electrodes ◽  
Low Field

ABSTRACTWe report the fabrication of ferromagnet-insulator-ferromagnet junction devices using a ramp-edge geometry based on (La0.7Sr0.3)MnO3 ferromagnetic electrodes and a SrTiO3 insulator. The multilayer thin films were deposited using pulsed laser deposition and the devices were patterned using photolithography and ion milling. As expected from the spin-dependent tunneling, the junction magnetoresistance depends on the relative orientation of the magnetization in the electrodes. The maximum junction magnetoresistance (JMR) of 30 % is observed below 300 Oe at low temperatures (T < 100 K).

The effect of target crystallography on the growth of Pb(Mg1/3Nb2/3)O3 thin films using pulsed laser deposition

1999 ◽  
Vol 14 (6) ◽  
pp. 2355-2358 ◽  
Author(s):  
M. H. Corbett ◽  
G. Catalan ◽  
R. M. Bowman ◽  
J. M. Gregg
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Growth Conditions ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Lead Magnesium

Pulsed laser deposition has been used to make two sets of lead magnesium niobate thin films grown on single-crystal h100j MgO substrates. One set was fabricated using a perovskite-rich target while the other used a pyrochlore-rich target. It was found that the growth conditions required to produce almost 100% perovskite Pb(Mg1/3Nb2/3)O3 (PMN) films were largely independent of target crystallography. Films were characterized crystallographically using x-ray diffraction and plan view transmission electron microscopy, chemically using energy dispersive x-ray analysis, and electrically by fabricating a planar thin film capacitor structure and monitoring capacitance as a function of temperature. All characterization techniques indicated that perovskite PMN thin films had been successfully fabricated.

Pulsed Laser Deposition of SrBi2Ta2O9 Thin Films for Nonvolatile Memory Applications

1995 ◽  
Vol 397 ◽  
Author(s):  
S. Werner ◽  
D. Thomas ◽  
S.K. Streiffer ◽  
O. Auciello ◽  
Angus I. Kingon
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Nonvolatile Memory ◽  
Elevated Temperatures ◽  
Sol Gel ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Laser Deposition ◽  
Polarization Electric Field ◽  
Memory Applications

ABSTRACTFerroelectric SrBi2Ta2U9 (SBT) thin films were synthesized by pulsed laser deposition (PLD) on platinized silicon substrates held at different substrate temperatures, from targets with different compositions. It was necessary to anneal films deposited at low temperature (525°C) at elevated temperatures in an oxygen atmosphere in order to achieve properties comparable to SBT thin films grown by the sol-gel technique. Polarization – electric field hysteresis loops showed saturation in the 2-5 V range with a remnant polarization 2Pr = 8-13 µC/cm2. Capacitors showed negligible fatigue up to 1010 switching cycles.

Pulsed Laser Deposition of BaxSr1-xTiO3 Thin Films for Frequency Agile Microwave Electronics

1998 ◽  
Vol 526 ◽  
Author(s):  
W. Chang ◽  
J. S. Horwitz ◽  
J. M. Pond ◽  
S. W. Kirchoefer ◽  
D B. Chrisey
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Dielectric Behavior ◽  
Laser Deposition ◽  
Film Stress ◽  
Bst Films ◽  
The Difference ◽  
Film Substrate

AbstractOriented, single phase thin films (~5000Å thick) of BaxSr1-xTiO3 (BST) have been deposited on to (100) MgO and LaAlO3 (LAO) single crystal substrates using pulsed laser deposition (PLD). A strong correlation is observed between the microstructure of the deposited film and the dielectric tuning and loss at microwave frequencies. Microstructural defects observed in as deposited films include strain, due to film substrate lattice mismatch and oxygen and cation vacancies. Compensation of the ablation target with excess Ba and Sr is observed to increase the dielectric constant and to reduce the dielectric loss. Post-deposition, bomb annealing of films at high temperatures (1250°C) is observed to fill oxygen vacancies and increase grain size. The difference in the dielectric behavior for as-deposited and low temperature annealed BST films on MgO and BST films on LAO is observed and may be attributed to the differences in film stress. A further improvement in the dielectric behavior is observed by the addition of donor/acceptor dopants such as Mn. The data shows that ferroelectric thin films can be used to build tunable microwave circuits that offer significant performance advantages over devices made from conventional semiconducting materials.

scholarly journals Epitaxial growth of β-Ga2O3 thin films on Ga2O3 and Al2O3 substrates by using pulsed laser deposition

2019 ◽  
Vol 09 (04) ◽  
pp. 1950032 ◽  
Author(s):  
Yuxin An ◽  
Liyan Dai ◽  
Ying Wu ◽  
Biao Wu ◽  
Yanfei Zhao ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Optical Transmittance ◽  
Laser Deposition ◽  
Ultraviolet Region ◽  
X Ray Diffraction ◽  
Chemical Cleaning ◽  
Transmission Electron ◽  
Xrd Patterns

In this work, we have successfully grown high quality epitaxial [Formula: see text]-Ga2O3 thin films on [Formula: see text]-Ga2O3 (100) and Al2O3(0001) substrates using pulsed laser deposition (PLD). By optimizing temperature and oxygen pressure, the best conditions were found to be 650–700∘C and 0.5[Formula: see text]Pa. To further improve the quality of hetero-epitaxial [Formula: see text]-Ga2O3, the sapphire substrates were pretreated for atomic terraced surface by chemical cleaning and high temperature annealing. From the optical transmittance measurements, the films grown at 600–750∘C exhibit a clear absorption edge at deep ultraviolet region around 250–275[Formula: see text]nm wavelength. High resolution transmission electron microscope (HRTEM) images and X-ray diffraction (XRD) patterns demonstrate that [Formula: see text]-Ga2O3(-201)//Al2O3(0001) epitaxial texture dominated the epitaxial oxide films on sapphire substrate, which opens up the possibilities of high power electric devices.

A Simple and Effective Route to Annihilate Defects in Nanocrystalline SnO2 Thin Films Prepared by Pulsed Laser Deposition

2007 ◽  
Vol 1026 ◽  
Author(s):  
Zhiwen Chen ◽  
C. M. L. Wu ◽  
C. H. Shek ◽  
J. K. L. Lai ◽  
Z. Jiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Pulsed Laser Deposition ◽  
Gas Sensors ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Sno2 Thin Films

AbstractThe microstructural defects of nanocrystalline SnO2 thin films prepared by pulsed laser deposition have been investigated using transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. Defects inside nanocrystalline SnO2 thin films could be significantly reduced by annealing the SnO2 thin films at 300 °C for 2 h. High-resolution transmission electron microscopy showed that stacking faults and twins were annihilated upon annealing. In particular, the edges of the SnO2 nanoparticles demonstrated perfect lattices free of defects after annealing. Raman spectra also confirmed that annealing the specimen was almost defect-free. By using thermal annealing, defect-free nanocrystalline SnO2 thin films can be prepared in a simple and practical way, which holds promise for applications as transparent electrodes and solid-state gas sensors.

Cation Ordering Structure in La0.8Ca0.2MnO3 Thin Films by Pulsed Laser Deposition

1999 ◽  
Vol 602 ◽  
Author(s):  
Y. H. Li ◽  
M. Rajeswari ◽  
A. Biswasl ◽  
D. J. Kang ◽  
C. Sehmen ◽  
...  
Keyword(s):  
Thin Films ◽  
Bulk Material ◽  
Pulsed Laser ◽  
Careful Analysis ◽  
Laser Deposition ◽  
Cation Ordering ◽  
Ordered Structure ◽  
Transmission Electron ◽  
Monoclinic Distortion ◽  
Microscopy Images

AbstractA careful analysis of high-resolution transmission electron microscopy images from La0.8Ca0.2MnO3 thin films indicates that the images can not explained based on either the classical Pnma structure or its monoclinic distortion. A cation ordered structure is proposed which could be responsible for the significantly higher Tc of the film (298K) compared with the bulk material of the same composition (190K).

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