Colossal Magnetoresisttve Tffin Films of (La1-x,Prx)0.7Ca0.3MnO3 Prepared by Aerosol MOCVD

1997 ◽  
Vol 495 ◽  
Author(s):  
O. Yu. Gorbenko ◽  
A. A. BOSAK ◽  
A. R. KAUL ◽  
N. A. BABUSHKINA ◽  
L. M. BELOVA
Keyword(s):  
Thin Films ◽  
Applied Field ◽  
Colossal Magnetoresistance ◽  
Tensile Strain ◽  
Large Angle ◽  
Critical Value ◽  
Epitaxial Films ◽  
Charge Ordering ◽  
Arrhenius Law ◽  
Chemical Pressure

ABSTRACTThin epitaxial films of (La1-x,Prx)0.7Ca0.3MnO3 (x=0,0.25,0.5,0.75,l) were grown on LaA1O3, SrTiO3 and ZrO2(Y2O3) by aerosol MOCVD at 750°C Variation of x greatly influences the electrical properties of material by changing of the tolerance factor t. The tensile strain in the films on perovskite substrates produces the effect on the maximum resistivity temperature Tp comparable with the effect of chemical pressure nearby critical value of t ∼ 0.91. By variation of x the colossal magnetoresistance in very low magnetic fields was achieved in the thin films: an applied field of 0.3 T was enough for 32 times decrease of the resistivity of (La0.35,Pr0.35)Ca0.3MnO3 film on LaA1O3 at 155 K. The charge ordering starting in (La1-x,Prx)0.7Ca0.3MnO3 at 160–210 K leads to the switching from Arrhenius law (lggρ ∼ T1 ) to Mott law (lgρ ∼ T1/4) of resistivity. Large-angle boundaries dominating the structure of the films on ZrO2(Y2O3) increase the resistivity both above and below Tp.

scholarly journals Alkali-deficiency driven charged out-of-phase boundaries for giant electromechanical response

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haijun Wu ◽  
Shoucong Ning ◽  
Moaz Waqar ◽  
Huajun Liu ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Stability ◽  
Epitaxial Films ◽  
Polarization Rotation ◽  
Phase Boundaries ◽  
Film Properties ◽  
New Strategy ◽  
The Matrix ◽  
Opposing Effects ◽  
Severe Deterioration

AbstractTraditional strategies for improving piezoelectric properties have focused on phase boundary engineering through complex chemical alloying and phase control. Although they have been successfully employed in bulk materials, they have not been effective in thin films due to the severe deterioration in epitaxy, which is critical to film properties. Contending with the opposing effects of alloying and epitaxy in thin films has been a long-standing issue. Herein we demonstrate a new strategy in alkali niobate epitaxial films, utilizing alkali vacancies without alloying to form nanopillars enclosed with out-of-phase boundaries that can give rise to a giant electromechanical response. Both atomically resolved polarization mapping and phase field simulations show that the boundaries are strained and charged, manifesting as head-head and tail-tail polarization bound charges. Such charged boundaries produce a giant local depolarization field, which facilitates a steady polarization rotation between the matrix and nanopillars. The local elastic strain and charge manipulation at out-of-phase boundaries, demonstrated here, can be used as an effective pathway to obtain large electromechanical response with good temperature stability in similar perovskite oxides.

scholarly journals Critical effect of the bottom electrode on the ferroelectricity of epitaxial Hf0.5Zr0.5O2 thin films

2021 ◽  
Author(s):  
Saúl Estandía ◽  
Jaume Gàzquez ◽  
María Varela ◽  
Nico Dix ◽  
Mengdi Qian ◽  
...  
Keyword(s):  
Thin Films ◽  
Bottom Electrode ◽  
Orthorhombic Phase ◽  
Epitaxial Films ◽  
Critical Effect

Comparison of a set of perovskite electrodes shows that La1−x(Ca,Sr)xMnO3 is critical to stabilize the ferroelectric orthorhombic phase in epitaxial films. The stabilization is favored if the La content in the manganite is high.

Cooperative enhancement of in-plane orbital ordering by oxygen deficiency and in-plane tensile strain in La 0.7 Sr 0.3 MnO 3−δ thin films

2007 ◽  
Vol 80 (3) ◽  
pp. 37003 ◽  
Author(s):  
C. Aruta ◽  
G. Balestrino ◽  
A. Tebano ◽  
G. Ghiringhelli ◽  
N. B. Brookes
Keyword(s):  
Thin Films ◽  
Tensile Strain ◽  
Oxygen Deficiency ◽  
Orbital Ordering

Contrasting effects of compressive and tensile strain and doping-induced opening of charge-transfer gap in NdNi[sub 0.90]Mn[sub 0.10]O[sub 3] thin films

2013 ◽  
Author(s):  
Mahesh Chandra ◽  
Amit Khare ◽  
Fozia Aziz ◽  
Rakesh Rana ◽  
D. S. Rana ◽  
...  
Keyword(s):  
Thin Films ◽  
Charge Transfer ◽  
Tensile Strain

scholarly journals Corrugated Photoactive Thin Films for Flexible Strain Sensor

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1970 ◽  
Author(s):  
Donghyeon Ryu ◽  
Alfred Mongare
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Tensile Strain ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Optical And Electrical Properties ◽  
Strain Sensing ◽  
Dc Voltage ◽  
Flexible Strain Sensor

In this study, a flexible strain sensor is devised using corrugated bilayer thin films consisting of poly(3-hexylthiophene) (P3HT) and poly(3,4-ethylenedioxythiophene)-polystyrene(sulfonate) (PEDOT:PSS). In previous studies, the P3HT-based photoactive non-corrugated thin film was shown to generate direct current (DC) under broadband light, and the generated DC voltage varied with applied tensile strain. Yet, the mechanical resiliency and strain sensing range of the P3HT-based thin film strain sensor were limited due to brittle non-corrugated thin film constituents. To address this issue, it is aimed to design a mechanically resilient strain sensor using corrugated thin film constituents. Buckling is induced to form corrugation in the thin films by applying pre-strain to the substrate, where the thin films are deposited, and releasing the pre-strain afterwards. It is known that corrugated thin film constituents exhibit different optical and electronic properties from non-corrugated ones. Therefore, to design the flexible strain sensor, it was studied to understand how the applied pre-strain and thickness of the PEDOT:PSS conductive thin film affects the optical and electrical properties. In addition, strain effect was investigated on the optical and electrical properties of the corrugated thin film constituents. Finally, flexible strain sensors are fabricated by following the design guideline, which is suggested from the studies on the corrugated thin film constituents, and the DC voltage strain sensing capability of the flexible strain sensors was validated. As a result, the flexible strain sensor exhibited a tensile strain sensing range up to 5% at a frequency up to 15 Hz with a maximum gauge factor ~7.

Influence of cooling rate on ferroelastic domain structure for epitaxial (100)/(001)-oriented Pb(Zr, Ti)O3 thin films under tensile strain

2021 ◽  
Author(s):  
Yoshitaka Ehara ◽  
Daichi Ichinose ◽  
Masanori Kodera ◽  
Takahisa Shiraishi ◽  
Takao Shimizu ◽  
...  
Keyword(s):  
Thin Films ◽  
Cooling Rate ◽  
Domain Structure ◽  
Tensile Strain

Charge - Ordered Manganeese Oxide Studied By Ω - Filter - Angular Resolved EELS

2001 ◽  
Vol 7 (S2) ◽  
pp. 1146-1147
Author(s):  
Y. Murooka ◽  
N. Tanaka ◽  
M. Hibino ◽  
K. Tsuda ◽  
M. Tanaka
Keyword(s):  
Electronic Structure ◽  
Colossal Magnetoresistance ◽  
Manganese Oxides ◽  
Charge Ordering ◽  
Nanometer Scale ◽  
Theoretical Studies ◽  
Optical Responses ◽  
Column Type ◽  
Valence Electrons ◽  
Electron Energy Loss

Despite of the intensive studies, Colossal Magnetoresistance (CMR) phenomena occurring in manganese oxides is still not fully understood. Theoretical studies based on an ordered crystal phase such as the charge-ordering (CO) phase have shown some successes in reproducing experimental evidences. Recently it was, however, shown that such a CO phase included giant clusters which were as large as 100 nm. This indicates the importance of the nanometer-scale information about the electronic structure to understand the CO. La0.5Sr1.5MnO4 is one of the oxides under intense investigations. in the CO phase, the eg valence electrons were found to be ordered at Mn sites. The optical responses of the CO clusters, however, has not been studied. in this study we have attempted to obtain such information from CO clusters in La0.5Sr1.5MnO4 by angular-resolved electron-energy-loss-spectroscopy (EELS) using an in-column type Ω-spectrometer.

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