Film thickness versus misfit strain phase diagrams for epitaxialPbTiO3ultrathin ferroelectric films

2008 ◽  
Vol 78 (6) ◽  
Author(s):  
Q. Y. Qiu ◽  
V. Nagarajan ◽  
S. P. Alpay
Keyword(s):  
Film Thickness ◽  
Phase Diagrams ◽  
Misfit Strain ◽  
Ferroelectric Films

Misfit Strain Relief Beyond the Critical Thickness Using Curvature Measurements and in Situ Characterization of the Magneto-Optic Kerr Effect

1994 ◽  
Vol 356 ◽  
Author(s):  
H. E. Inglefield ◽  
G. Bochi ◽  
C. A. Ballentine ◽  
R. C. O’Handley ◽  
C. V. Thompson
Keyword(s):  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Kerr Effect ◽  
Critical Thickness ◽  
Misfit Strain ◽  
Misfit Dislocations ◽  
Wafer Curvature ◽  
Curvature Measurements ◽  
Magneto Optic

AbstractEpitaxial misfit has been characterized in Ni/Cu/Si (100) as a function of Ni film thickness using wafer curvature measurements. This strain can be related to measurements of magnetic anisotropy made in the deposition system using the magneto-optic Kerr effect. Films were deposited using molecular beam epitaxy (MBE) with varying Ni epilayer thickness between 10 and 1000Å. The change in wafer curvature due to misfit strain was measured using optical interferometry and the strain was calculated using Stoney’s equation. Transmission electron microscopy was used to characterize misfit dislocations at the Ni/Cu interface. It has been determined that misfit strain can have a very strong effect on magnetic anisotropy, particularly in the regime between the critical thickness and complete misfit accommodation, where strain has been found to decrease significantly as a function of film thickness. A critical strain has been determined at which a transition in the direction of magnetization easy axis from perpendicular to the film to in the film plane occurs. This discovery allows the use of Kerr effect measurements to characterize misfit strain in situ.

scholarly journals Phase Diagrams of Instabilities in Compressed Film-Substrate Systems

2013 ◽  
Vol 81 (5) ◽  
Author(s):  
Qiming Wang ◽  
Xuanhe Zhao
Keyword(s):  
Phase Transitions ◽  
Film Thickness ◽  
Phase Diagrams ◽  
Stability Criterion ◽  
Theoretical Study ◽  
Membrane Stress ◽  
Substrate Adhesion ◽  
Elastic Film ◽  
Quantitative Understanding ◽  
Film Substrate

Subject to a compressive membrane stress, an elastic film bonded on a substrate can become unstable, forming wrinkles, creases or delaminated buckles. Further increasing the compressive stress can induce advanced modes of instabilities including period-doubles, folds, localized ridges, delamination, and coexistent instabilities. While various instabilities in film-substrate systems under compression have been analyzed separately, a systematic and quantitative understanding of these instabilities is still elusive. Here we present a joint experimental and theoretical study to systematically explore the instabilities in elastic film-substrate systems under uniaxial compression. We use the Maxwell stability criterion to analyze the occurrence and evolution of instabilities analogous to phase transitions in thermodynamic systems. We show that the moduli of the film and the substrate, the film-substrate adhesion strength, the film thickness, and the prestretch in the substrate determine various modes of instabilities. Defects in the film-substrate system can facilitate it to overcome energy barriers during occurrence and evolution of instabilities. We provide a set of phase diagrams to predict both initial and advanced modes of instabilities in compressed film-substrate systems. The phase diagrams can be used to guide the design of film-substrate systems to achieve desired modes of instabilities.

Magnetic Structures in Nonmag-/MAG-/Nonmag-Netic Sandwiches

1995 ◽  
Vol 384 ◽  
Author(s):  
Yoshiyuki Kawazoe ◽  
Xiao Hu
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Phase Diagrams ◽  
Exchange Coupling ◽  
Spin Reorientation ◽  
Scaling Relations ◽  
Magnetic Thin Film ◽  
Magnetic Structures ◽  
Spin Reorientation Transition ◽  
Variational Formalism

ABSTRACTSpin-reorientation transition in magnetic thin film sandwiched by nonmagnetic materials is clarified by means of the variational formalism. Phase diagrams of the magnetization configuration are presented. Scaling relations among the film thickness, exchange coupling and magnetic anisotropies are revealed. A formula for the interface anisotropy is presented.

Epitaxial PMN-PT Relaxor Thin Films: Dependence of Dielectric and Piezoelectric Properties on Film Thickness

1999 ◽  
Vol 596 ◽  
Author(s):  
V. Nagarajan ◽  
S. P. Alpay ◽  
C. S. Ganpule ◽  
B. Nagaraj ◽  
S. Aggarwal ◽  
...  
Keyword(s):  
Film Thickness ◽  
Piezoelectric Properties ◽  
Relative Dielectric Constant ◽  
Misfit Strain ◽  
Lead Magnesium Niobate ◽  
Oxide Electrodes ◽  
Order Of Magnitude ◽  
Lead Magnesium ◽  
Probe Microscope ◽  
Pt Films

AbstractThe effect of substrate induced constraint and misfit strain on the structure and piezoelectric properties of epitaxial relaxor ferroelectric lead magnesium niobate-lead titanate (PMN-PT) films were investigated. Relaxor PMN-PT epitaxial 100–400 nm thick films with top and bottom oxide electrodes were grown by pulsed laser deposition on (100) LaAlO3 substrates. A systematic decrease in the temperature of the dielectric maximum with increasing film thickness was observed. This is accompanied by an increase in the room temperature relative dielectric constant. The longitudinal piezoelectric coefficient measured using a scanned probe microscope, increases by almost an order of magnitude with increasing film thickness.

scholarly journals Thickness- and temperature-dependent structural and electromechanical properties of (100)-oriented Sc-doped (Na0.85K0.15)0.5Bi0.5TiO3 ferroelectric films

RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44136-44143
Author(s):  
Yunyi Wu ◽  
Yonghong Hu ◽  
Xiaohui Wang ◽  
Caifu Zhong ◽  
Longtu Li
Keyword(s):  
Film Thickness ◽  
Composite Films ◽  
Temperature Dependent ◽  
Electromechanical Properties ◽  
Ferroelectric Films

NKBT-Sc film thickness- and LNO layer insertion mode-dependent structural and electromechanical properties of the composite films were investigated.

Ferroelectric and Pyroelectric Properties of Nano Graded Ferroelectric Films

2011 ◽  
Vol 403-408 ◽  
pp. 1077-1082
Author(s):  
Hui Chen ◽  
Tai Min Cheng
Keyword(s):  
Transition Temperature ◽  
Film Thickness ◽  
Spontaneous Polarization ◽  
Local Structure ◽  
Numerical Results ◽  
Ferroelectric Films ◽  
Polarization Distribution ◽  
Ginzburg Landau ◽  
Pyroelectric Properties ◽  
Lower Transition

In order to improve the properties of nano graded ferroelectric films (NGFF), the generalized Ginzburg-Landau-Denvonshire (GLD) theory is used to investigate the ferroelectric and pyroelectric properties of NGFF. A function is introduced to describe the local structure of this graded film. The numerical results show that parameter and film thickness are two very important factors that influence the ferroelectric and pyroelectric properties of films, larger values lead to smaller spontaneous polarization and lower pyroelectric peak Local structure in NGFF leads to flatten the polarization distribution, which raises the spontaneous polarization of components with lower transition temperature, but reduces spontaneous polarization of components with higher transition temperature.

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