Strain induced super-paramagnetism in Cr2O3 in the ultra thin film limit

2015 ◽  
Vol 1729 ◽  
pp. 79-83 ◽  
Author(s):  
Iori Tanabe ◽  
Haseeb Kazi ◽  
Yuan Cao ◽  
Jack L Rodenburg ◽  
Takashi Komesu ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Ordering ◽  
Hysteresis Effect ◽  
Strain Effect ◽  
Temperature Hysteresis ◽  
Antiferromagnetic Ordering ◽  
Show Evidence ◽  
Higher Temperature ◽  
Ultra Thin Film

ABSTRACTUltra thin films of chromia (Cr2O3), less than 3 nm thick, grown epitaxial on α-Al2O3 (sapphire), and are thus compressively strained in-plane. The resulting films show evidence of some magnetic ordering above the Néel temperature of chromia (307 K). The observed higher temperature hysteresis effect observed are very likely a strain effect, and not associated with the typical antiferromagnetic ordering expected of chromia.

The interdiffusion of Cu, Co and Au Thin Films at elevated temperatures

1989 ◽  
Vol 167 ◽  
Author(s):  
Peter Madakson ◽  
Joyce C. Liu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Elevated Temperatures ◽  
Higher Temperature ◽  
Au Thin Films ◽  
Au Thin Film

AbstractA detailed study of the interdiffusion and resistivity of Cu/Au, Cu/Co/ Co/Au and Cu/Co/Au thin film structures was carried out at temperatures ranging from 25 to 550°C1. Both Cu and Au, in the Cu/Au structure, intermix readily even at temperatures as low as 150°C and the interdiffusion is accompanied by rapid increase in resistivity. Very little interdiffusion occurs in the Cu/Co, Co/Au or Cu/Co/Au thin film structures up to about 400°C, after which the resistivity increases. The very rapid increase in resistivity observed at 250°C for the Cu/Au system and at 450°C for Cu/Co/Au, is associated with recrystallization of the films into large grains and the formation of AuCu, Cu3Au and Cu3Au2 compounds. The Cu/Co/Au structure recrystallizes at a higher temperature because of the time needed for Cu and Au to diffuse through the Co layer, which did not react significantly with either Au or Cu.

ESR STUDY OF CuO BULK POWDER AND THIN FILMS

1992 ◽  
Vol 06 (16n17) ◽  
pp. 1043-1047 ◽  
Author(s):  
ALEX PUNNOOSE ◽  
JILSON MATHEW ◽  
B. P. MAURYA ◽  
MOHD. UMAR ◽  
R. J. SINGH
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Resonance Investigation ◽  
Antiferromagnetic Ordering ◽  
Bulk Powder ◽  
Complete Destruction ◽  
Spin Resonance ◽  
Different Temperatures ◽  
Electron Spin Resonance Investigation ◽  
Film Form

A systematic Electron Spin Resonance investigation is carried out in CuO bulk powder and thin films, after calcining them to different temperatures ranging from 100°C to 1000°C. In CuO powder, two separate signals (one broad and one sharp) were observed at calcination temperature of 500°C, for the fist time. They got intensified, came closer and amalgamated on further heating upto 800°C, indicating complete destruction of antiferromagnetic ordering in this powdered compound. In thin films of CuO, the first appearance of the signal at 200°C and its intensification and shifting on further heating indicates that in thin film form, the destruction of antiferromagnetism takes place much earlier.

Microstructure and Strain in GaAs/AlGaAs MQW thin Films Bonded to Different Substrates by Eutectic Alloying

1994 ◽  
Vol 356 ◽  
Author(s):  
C. H. Lin ◽  
H. C. Kuo ◽  
Y. Lu ◽  
H. Shen ◽  
J. Pamulapati ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Plane Strain ◽  
Multiple Quantum Well ◽  
Strain Effect ◽  
Multiple Quantum ◽  
New Device ◽  
Device Applications ◽  
Bonding Technique

AbstractResearch of the strain effect on semiconductors and their heterostructures has generated increasing interests due to its important device applications. We have developed a eutectic bonding technique to create in-plane anisotropic strain in GaAs/AlGaAs multiple quantum well (MQW) thin films. MQW thin films grown on (100) GaAs substrates were bonded to (100) GaAs, (100) Si and Y-cut LiNbO3 submounts with a Au/Sn eutectic alloy. The bonding materials consist of Au/Sn multilayer (80 wt% Au and 20 wt% Sn; 0.95μm) with a Cr (500Å) adhesion layer. The bonding process was optimized by carefully choosing the annealing conditions. After bonding, the substrates of the MQWs were removed by wet chemical etching. The in-plane strain was induced in MQW thin film due to the different thermal expansion between the thin film and submount. The strain was characterized using X-ray rocking curve. The microstructures of bonding interfaces and MQW thin films were examined by scanning electron microscope(SEM) and cross-section transmission electron microscope (XTEM). This bonding technique can be used for many new device applications which take the advantage of in-plane strain, as well as for device integration.

scholarly journals Corrugated Photoactive Thin Films for Flexible Strain Sensor

2018 ◽  
Author(s):  
Donghyeon Ryu ◽  
Alfred Mongare
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Tensile Strain ◽  
Strain Sensor ◽  
Strain Effect ◽  
Optical And Electrical Properties ◽  
Strain Sensing ◽  
Dc Voltage ◽  
Flexible Strain Sensor

In this study, a flexible strain sensor is devised using corrugated poly(3-hexylthiophene) (P3HT) thin film. In the previous studies, the P3HT-based photoactive 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 relatively more brittle thin film constituent—poly(3,4-ethylenedioxythiophene)-polystyrene(sulfonate) (PEDOT:PSS) conductive thin film as a bottom electrode. To address this issue, it is aimed to design 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 optimize design of the flexible strain sensor, it was studied to understand how the applied pre-strain and thickness of the PEDOT:PSS thin film affect the optical and electrical properties. Also, pre-strain effect on light absorptivity of the corrugated P3HT-based thin films was studied. 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 DC voltage strain sensing capability was validated. As a result, flexible strain sensor exhibited tensile strain sensing range up to 5% at frequency up to 15 Hz with maximum gage factor ~7.

Growth of La2−x SrxCuO4 and La2CuO4+δ thin films by Reactive Coevaporation

1997 ◽  
Vol 502 ◽  
Author(s):  
H. Sato ◽  
H. Yamamoto ◽  
M. Naito
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Ultrathin Films ◽  
Film Growth ◽  
Lattice Mismatch ◽  
Compressive Strain ◽  
Thin Film Growth ◽  
Strain Effect ◽  
High Quality ◽  
Substrate Dependence

ABSTRACTThin films of La2−xSrxCuO4 (LSCO) and La2CuO4+δ (LCO) were grown by reactive coevaporation. We obtained LSCO thin films on (001) LaSrA104 (LSAO) substrates with Tc(R=0) = 44 K, which is higher than that for bulk samples. A structural analysis indicates that the increase in Tc is due to compressive strain generated by the lattice mismatch. A similar strain effect is suggested from the substrate dependence of Tc for superconducting LCO thin films, for which Tc(R=0) reached 50 K on (001) LSAO substrates. We also succeeded in obtaining high-quality LSCO ultrathin films without any buffer or cap layers on (001) LSAO substrates, but not on substrates of other materials with the larger lattice mismatch with LSCO. These results demonstrate that the lattice mismatch with the substrates is important in thin-film growth of LSCO and LCO.

Characterization of High-Speed Microactuator Utilizing Shape Memory Alloy Thin Films

2005 ◽  
Vol 475-479 ◽  
pp. 2037-2042 ◽  
Author(s):  
M. Tomozawa ◽  
K. Okutsu ◽  
Hee Young Kim ◽  
Shuichi Miyazaki
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformation ◽  
Transformation Temperature ◽  
High Speed ◽  
Temperature Hysteresis ◽  
High Transformation ◽  
Working Frequency ◽  
Increasing Temperature

Dynamic actuation properties of two types of high-speed microactuators utilizing Ti-Ni-based thin films were investigated. One type is a microactuator utilizing a Ti-Ni-Pd thin film which has high transformation temperatures. Cooling rate of a microactuator increases with increasing temperature difference between transformation and atmosphere temperatures, thus the increase in transformation temperature is effective to increase the actuation response. The other type is a microactuator using R-phase transformation of a Ti-Ni thin film which has a narrow transformation temperature hysteresis. The narrow transformation temperature hysteresis of the R-phase transformation is effective to increase the actuation response. Both types of actuators are promising for high response applications. The working frequency of the microactuators reached 100Hz in the two types of microactuators utilizing the martensitic transformation of the Ti-Ni-Pd thin film and the R-phase transformation of the Ti-Ni thin film.

Thickness Dependencies in the Calculated Properties of Metallic Ultra-Thin Films

1997 ◽  
Vol 492 ◽  
Author(s):  
J. C. Boettger
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electronic Structure ◽  
Surface Properties ◽  
Electronic Structure Calculations ◽  
Structure Calculations ◽  
Ultra Thin Film

ABSTRACTUltra-thin film (UTF) electronic structure calculations are a common tool for investigating surface properties. In this work, electronic structure calculations for A1(111) films ranging from one to twelve atoms thick are used to illustrate some of the difficulties that can arise when one attempts to determine surface properties of metals with UTF calculations.

Theoretical Studies of Spin Dependent Scatterings of Electrons from Ferromagnetic Surfaces and Ultra Thin Films

1991 ◽  
Vol 231 ◽  
Author(s):  
A. Ormeci ◽  
M. P. Gokhale ◽  
Burl M. Hall ◽  
D. L. Mills
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Ab Initio ◽  
Ground State ◽  
Theoretical Studies ◽  
Angle Variation ◽  
Spin Dependent Scattering ◽  
Ultra Thin Film

AbstractWe summarize results of our recent theoretical studies of spin dependent scattering of electrons from ferromagnetic surfaces. We obtain an excellent account of both the energy and angle variation of the exchange asymmetry reported by Waller and Gradmann in their SPLEED study of the Fe(110) surface, and of spin dependent asymmetries in the transmission of photoelectrons through an ultra thin film of Fe on Cu(100). Potentials supplied by Fu and Freeman enable us to account for the data, with use of ground state potentials generated by ab initio methods.

scholarly journals Structure and magnetism in Ga-rich MnGa/GaN thin films and unexpected giant perpendicular anisotropy in the ultra-thin film limit

2016 ◽  
Vol 367 ◽  
pp. 312-319 ◽  
Author(s):  
Andrada-Oana Mandru ◽  
Joseph P. Corbett ◽  
Jeremy M. Lucy ◽  
Andrea L. Richard ◽  
Fengyuan Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Perpendicular Anisotropy ◽  
Ultra Thin Film
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