Dependence on film thickness of grain boundary low-field magnetoresistance in thin films of La0.7Ca0.3MnO3

2001 ◽  
Vol 89 (11) ◽  
pp. 6970-6972 ◽  
Author(s):  
N. K. Todd ◽  
N. D. Mathur ◽  
M. G. Blamire
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Film Thickness ◽  
Low Field

scholarly journals Interfacial reconstruction in La0.7Sr0.3MnO3 thin films: giant low-field magnetoresistance

2020 ◽  
Vol 2 (7) ◽  
pp. 2792-2799
Author(s):  
Umesh Kumar Sinha ◽  
Bibekananda Das ◽  
Prahallad Padhan
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Low Field

The 200 Å thick La0.7Sr0.3MnO3 film grown on (001) oriented LaAlO3 at 300 mT field exhibits 60% MR, which decreases with an increase in the La0.7Sr0.3MnO3 film thickness due to a decrease in the non-collinear Mn ion spins near the interface.

Chemical stresses induced by grain-boundary diffusion in thin films

2001 ◽  
Vol 16 (7) ◽  
pp. 1967-1974 ◽  
Author(s):  
W. L. Wang ◽  
Y. T. Chou ◽  
Sanboh Lee
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Film Thickness ◽  
Maximum Stress ◽  
Infinite System ◽  
Boundary Diffusion ◽  
Electronic Device ◽  
Local Stress ◽  
Grain Boundary Diffusion ◽  
Tension And Compression

Chemical stresses induced by grain-boundary diffusion in thin films were analyzed. The stress distribution consisted of both tension and compression fields, and its characteristics were similar to those obtained for a semi-infinite solid. At a given time, the maximum stress (tension or compression) increased with increasing film thickness for both constant and instantaneous sources; it was generally higher than that in the semi-infinite system. The maximum stress (tension or compression) decreased as the diffusion time increased and at a given time and film thickness it increased with decreasing diffusivity ratio. The buildup of local stress is likely to cause damage and malfunctions of the film when used in an electronic device.

Capillary Instabilities in Thin, Polycrystalline Films

1985 ◽  
Vol 47 ◽  
Author(s):  
David J. Srolovitz ◽  
S. A. Safran
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Grain Boundary ◽  
Film Thickness ◽  
Critical Size ◽  
Equilibrium Contact Angle ◽  
Polycrystalline Films ◽  
Capillary Instabilities ◽  
Thin Polycrystalline ◽  
Grain Boundary Grooves

ABSTRACTThin films can break up into islands only if they are perturbed by substrate-intersecting perturbations. Grain boundary grooves and vertex pits are typical defects which nucleate holes in these films. Holes which exceed a critical size - proportional to the ratio of the film thickness to the equilibrium contact angle - grow, eventually disconnecting the film.

scholarly journals Optimization of electrical conductivity of SnS thin film of 0.2 < t ≤ 0.4 μm thicknes for field effect transistor application

2021 ◽  
Vol 67 (2 Mar-Apr) ◽  
pp. 263
Author(s):  
T. O. Daniel ◽  
U. E. Uno ◽  
K. U. Isah ◽  
U. Ahmadu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Grain Boundary ◽  
Film Thickness ◽  
Threshold Voltage ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Effect Transistor

This study is focused on the investigation of SnS thin film for transistor application. Electron trap which is associated with grain boundary effect affects the electrical conductivity of SnS semiconductor thin film thereby militating the attainment of the threshold voltage required for transistor operation. Grain size and grain boundary is a function of a semiconductor’s thickness. SnS semiconductor thin films of 0.20, 0.25, 0.30, 0.35, 0.40 μm were deposited using aerosol assisted chemical vapour deposition on glass substrates. Profilometry, Scanning electron microscope, Energy dispersive X-ray spectroscopy and hall measurement were used to characterise the composition, microstructure and electrical properties of the SnS thin film.  SnS thin films were found to consist of Sn and S elements whose composition varied with increase in thickness. The film conductivity was found to vary with grain size and grain boundary which is a function of the film thickness. The SnS film of 0.4 μm thickness shows optimal grain growth with a grain size of 130.31 nm signifying an optimum for the as deposited SnS films as the larger grains reduces the number of grain boundaries and charge trap density which allows charge carriers to move freely in the lattice thereby causing a reduction in resistivity and increase in conductivity of the films which is essential in obtaining the threshold voltage for a transistor semiconductor channel layer operation. The carrier concentration of due to low resistivity of 3.612 ×105 Ωcm of 0.4 μm SnS thin film thickness is optimum and favours the attainment of the threshold voltage for a field effect transistor operation hence the application of SnS thin film as a semiconductor channel layer in a field effect transistor.

Grain Boundary Curvature in Polycrystalline Metallic Thin Films

2000 ◽  
Vol 615 ◽  
Author(s):  
Alexander H. King ◽  
Rakesh Mangat ◽  
Kwame Owusu-Boahen
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Film Thickness ◽  
Sheet Thickness ◽  
Film Plane ◽  
Thickness Effect ◽  
Metallic Thin Films ◽  
Boundary Curvature ◽  
Grain Boundary Grooves

ABSTRACTWell-annealed thin films are typically observed to exhibit mean grain diameters that are approximately equal to the film thickness. The standard explanation of this “sheet thickness effect” is that it results from a balance of grain boundary curvature in two different directions which, in turn, results from pinning at grain boundary grooves. TEM experiments have been performed to assess this model, and it is found that the predicted curvature about axes in the film plane is absent. Alternate explanations of the sheet thickness effect are considered.

Agglomeration of Cobalt Silicide Films

1990 ◽  
Vol 202 ◽  
Author(s):  
Z. G. Xiao ◽  
G. A. Rozgonyi ◽  
C. A. Canovai ◽  
C. M. Osburn
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Grain Size ◽  
Grain Boundary ◽  
Film Thickness ◽  
Film Formation ◽  
Boundary Migration ◽  
Boundary Energy ◽  
Si Substrates ◽  
Probe Measurements

ABSTRACTThe agglomeration of Co silicide films formed on Si substrates processed with different Co film thickness was investigated by TEM, XRD, and four-point-probe measurements. It was found that thermal grooving always accompanies the film formation, while islanding can occur during high temperature thermal stability testing, or during formation of very thin films at moderate temperatures. In addition to whole film agglomeration, partial agglomeration on the top of the film has been observed, which is prominent and important for thin films. A theoretical model of agglomeration for silicide films is presented, which shows that when the ratio of grain size to film thickness is smaller than a critical value, the film will not lose its continuity. Also, grain boundary migration was found to have a suppressing effect on thermal grooving. Both a small grain size and a low grain boundary energy are shown to be favorable for improving the thermal stability.

Oxidation kinetics of nanocrystalline Al thin films

2019 ◽  
Vol 66 (5) ◽  
pp. 638-643
Author(s):  
Jinsong Luo ◽  
Ligong Zhang ◽  
Haigui Yang ◽  
Nan Zhang ◽  
Yongfu Zhu ◽  
...  
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Grain Boundary ◽  
Film Thickness ◽  
Silicon Substrate ◽  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Boundary Diffusion ◽  
Content Type ◽  
Kinetics Of

Purpose This paper aims to study the oxidation kinetics of the nanocrystalline Al ultrathin films. The influence of structure and composition evolution during thermal oxidation will be observed. The reason for the change in the oxidation activation energy on increasing the oxidation temperature will be discussed. Design/methodology/approach Al thin films are deposited on the silicon wafers as substrates by vacuumed thermal evaporation under the base pressure of 2 × 10−4 Pa, where the substrates are not heated. A crystalline quartz sensor is used to monitor the film thickness. The film thickness varies in the range from 30 to 100 nm. To keep the silicon substrate from oxidation during thermal oxidation of the Al film, a 50-nm gold film was deposited on the back side of silicon substrate. Isothermal oxidation studies of the Al film were carried out in air to assess the oxidation kinetics at 400-600°C. Findings The activation energy is positive and low for the low temperature oxidation, but it becomes apparently negative at higher temperatures. The oxide grains are nano-sized, and γ-Al2O3 crystals are formed at above 500°C. In light of the model by Davies, the grain boundary diffusion is believed to be the reason for the logarithmic oxidation rate rule. The negative activation energy at higher temperatures is apparent, which comes from the decline of diffusion paths due to the formation of the γ-Al2O3 crystals. Originality/value It is found that the oxidation kinetics of nanocrystalline Al thin films in air at 400-600°C follows the logarithmic law, and this logarithmic oxidation rate law is related to the grain boundary diffusion. The negative activation energies in the higher temperature range can be attributed to the formation of γ-Al2O3 crystal.

The Effects of Film Thickness and Texture on the high and Low-Field stress Response of Lead Zirconate Titanate Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
J. F. Shepard ◽  
F. Chu ◽  
B. Xu ◽  
S. Trolier-McKinstry
Keyword(s):  
Thin Films ◽  
Stress Response ◽  
Domain Wall ◽  
Film Thickness ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Biaxial Stress ◽  
Field Stress ◽  
Low Field ◽  
Zirconate Titanate

ABSTRACTLead zirconate titanate (PZT) thin films are currently employed in non-volatile ferroelectric memories (FRAM's) and are intended to be used as the active material in a number of microelectromechanical systems (MEMS). Several groups have reported that both the piezoelectric and dielectric characteristics of ferroelectric thin films improve with an increase of film thickness, though the reasons for those improvements are unclear. Previous investigations on the effects of biaxial mechanical stress indicate that non-180° domain wall motion is limited in PZT 52/48 films less than 0.5 μm thick. It is possible that some of the improvements of the dielectric and piezoelectric characteristics reported for thicker films (i.e. films thicker than 0.5 μm) are associated with an increase of extrinsic contributions to the properties. To evaluate domain wall mobility in thicker films, the high and low-field stress response of sol-gel PZT fabricated with either rapid thermal processing or conventional furnace annealing were investigated. Films with thicknesses ranging from 0.6 to 5.0 μm thick were measured as a function of applied biaxial stress (±110 MPa). It was found that for all films tested the changes of capacitance were on the order of 2–3%. High-field measurements showed: (1) the coercive field to be insensitive to applied stress, (2) remanent polarizations to decrease about 20% at the maximum applied tension, (3) remanent polarizations to increase less than 10% with applied compression, and (4) all changes to be reversible over the stress range investigated. These results suggest that extrinsic contributions are limited for the films tested.

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