Structural and Magneto-Electric Properties of Pulsed Laser Deposited Ferroelectric/Ferromagnetic Heterostructure

2009 ◽  
Vol 1199 ◽  
Author(s):  
Ricardo Martinez ◽  
Ashok Kumar ◽  
Ratnakar Palai ◽  
Ram S. Katiyar

AbstractAsymmetric superlattices (SLs) with ferromagnetic La0.7Sr0.3MnO3 (LSMO) and ferroelectric Ba0.7Sr0.3TiO3 (BST) as constitutive layers were fabricated on conducting LaNiO3 (LNO) coated (001) oriented MgO substrates using pulsed laser deposition (PLD). The crystallinity, ferroelectric and magnetic properties of the SLs were studied over a wide range of temperatures and frequencies. The structure exhibited ferromagnetic behavior at 300K, and ferroelectric behavior over a range of temperatures between 100K and 300K. The dielectric response as a function of frequency obeys normal behavior below 300 K, whereas it follows Maxwell–Wagner model at elevated temperatures. The effect of ferromagnetic LSMO layers on ferroelectric properties of the SL indicated strong influence of the interfaces. The asymmetric behavior of ferroelectric loop and the capacitance-voltage relationship suggest development of a built field in the SLs due to high strain across the interfaces.

2007 ◽  
Vol 1034 ◽  
Author(s):  
Ayan Roy Chaudhuri ◽  
S.B. Krupanidhi

AbstractSymmetric and asymmetric superlattices (SLs) composed of ferromagnetic La0.6Sr0.4MnO3 (LSMO) and ferroelectric 0.7Pb(Mg1/3Nb2/3)O3 – 0.3PbTiO3 (PMN-PT) with different periodicities have been fabricated on LaNiO3 (LNO) coated LaAlO3 (100) (LAO) substrates by pulsed laser ablation deposition. Structural, ferromagnetic and ferroelectric properties have been studied for all the SLs. All the heterostructures exhibited good ferromagnetic response over a wide range of temperatures (10K – 300K), whereas only the asymmetric SLs exhibited reasonably good ferroelectric behaviour. Ferromagnetic and ferroelectric hysteresis loops observed in the asymmetric SLs confirmed their biferroic nature. Studies were conducted towards understanding the influence of LSMO layers on the electrical responses of the heterostructures. Absence of ferroelectricity in the symmetric SL structures has been attributed to their high leakage characteristics. Strong influence of an applied magnetic field of 1.2T was observed on the ferroelectric properties of the asymmetric SLs. The effect of magnetic field on the ferroelectric properties of the SLs indicated possibility of strong interfacial effect.


Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.


Author(s):  
S. G. Ghonge ◽  
E. Goo ◽  
R. Ramesh ◽  
R. Haakenaasen ◽  
D. K. Fork

Microstructure of epitaxial ferroelectric/conductive oxide heterostructures on LaAIO3(LAO) and Si substrates have been studied by conventional and high resolution transmission electron microscopy. The epitaxial films have a wide range of potential applications in areas such as non-volatile memory devices, electro-optic devices and pyroelectric detectors. For applications such as electro-optic devices the films must be single crystal and for applications such as nonvolatile memory devices and pyroelectric devices single crystal films will enhance the performance of the devices. The ferroelectric films studied are Pb(Zr0.2Ti0.8)O3(PLZT), PbTiO3(PT), BiTiO3(BT) and Pb0.9La0.1(Zr0.2Ti0.8)0.975O3(PLZT).Electrical contact to ferroelectric films is commonly made with metals such as Pt. Metals generally have a large difference in work function compared to the work function of the ferroelectric oxides. This results in a Schottky barrier at the interface and the interfacial space charge is believed to responsible for domain pinning and degradation in the ferroelectric properties resulting in phenomenon such as fatigue.


Alloy Digest ◽  
1975 ◽  
Vol 24 (5) ◽  

Abstract USS TENELON is a completely austenitic, nickel-free stainless steel with exceptionally high strength which is retained at elevated temperatures. It has excellent corrosion resistance in atmospheric and mild acid exposures and maintains nonmagnetic characteristics even when 60% cold reduced. It also has good stress-rupture and creep properties in the range 1200-1500 F. It has a wide range of applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-311. Producer or source: United States Steel Corporation.


2003 ◽  
Vol 83 (26) ◽  
pp. 5500-5502 ◽  
Author(s):  
J.-R. Duclère ◽  
M. Guilloux-Viry ◽  
V. Bouquet ◽  
A. Perrin ◽  
E. Cattan ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
John B. Lowe ◽  
Richard T. Baker

Ordered mesoporous silica materials are of interest for a wide range of applications. In many of these, elevated temperatures are used either in the preparation of the material or during its use. Therefore, an understanding of the effect of high temperature treatments on these materials is desirable. In this work, a detailed structural study is performed on silicas with three representative pore structures: a 2-D hexagonal pore arrangement (SBA-15), a continuous 3D cubic bimodal pore structure (KIT-6), and a 3D large cage pore structure (FDU-12). Each silica is studied as prepared and after treatment at a series of temperatures between 300 and 900°C. Pore structures are imaged using Transmission Electron Microscopy. This technique is used in conjunction with Small-Angle X-ray Diffraction, gas physisorption, and29Si solid state Nuclear Magnetic Resonance. Using these techniques, the pore size distributions, the unit cell dimensions of the mesoporous structures, and the relative occupancy of the distinct chemical environments of Si within them are cross correlated for the three silicas and their evolution with treatment temperature is elucidated. The physical and chemical properties before, during, and after collapse of these structures at high temperatures are described as are the differences in behavior between the three silica structures.


2012 ◽  
Vol 1424 ◽  
Author(s):  
M. A. Mamun ◽  
A. H. Farha ◽  
Y. Ufuktepe ◽  
H. E. Elsayed-Ali ◽  
A. A. Elmustafa

ABSTRACTNanomechanical and structural properties of pulsed laser deposited niobium nitride thin films were investigated using X-ray diffraction, atomic force microscopy, and nanoindentation. NbN film reveals cubic δ-NbN structure with the corresponding diffraction peaks from the (111), (200), and (220) planes. The NbN thin films depict highly granular structure, with a wide range of grain sizes that range from 15-40 nm with an average surface roughness of 6 nm. The average modulus of the film is 420±60 GPa, whereas for the substrate the average modulus is 180 GPa, which is considered higher than the average modulus for Si reported in the literature due to pile-up. The hardness of the film increases from an average of 12 GPa for deep indents (Si substrate) measured using XP CSM and load control (LC) modes to an average of 25 GPa measured using the DCM II head in CSM and LC modules. The average hardness of the Si substrate is 12 GPa.


2004 ◽  
Vol 84 (7) ◽  
pp. 1165-1167 ◽  
Author(s):  
A. R. James ◽  
Chandra Prakash

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