Giant Magnetoresistance in Single Layer and Multilayer Phase Separating Alloy Films

1993 ◽  
Vol 313 ◽  
Author(s):  
S. Hossain ◽  
A. Waknis ◽  
D. Seale ◽  
M. Tan ◽  
M.R. Parker ◽  
...  
Keyword(s):  
Thin Films ◽  
Field Dependence ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Single Layer ◽  
Multilayer Films ◽  
Equilibrium Conditions ◽  
Ferromagnetic Layers ◽  
Novel Processing ◽  
New Phase

ABSTRACTThe phenomenon of giant magnetoresistance (GMR), previously measured only in multilayer films comprising ferromagnetic layers separated by nonmagnetic spacers, has recently been observed in single layer ‘granular’ alloy thin films prepared by cosputtering a ferromagnet and a nonmagnet which tend to phase separate (cluster) under equilibrium conditions. We have systematically studied the magnetoresistance of two new phase separating GMR systems (Ni66Fe16Co18-Ag and Co9oFelo-Ag) both of which exhibit large room temperature GMR (>11% and >14%, respectively). We have also attempted to influence the details of the field dependence of the magnetoresistance in the previously studied Co-Ag system by employing novel processing methods including interrupted sputtering and layering of the Co-Ag alloy with Cu spacers.

Giant Magnetoresistance in Hybrid Magnetic Nanostructures Including Both Layers and Clusters

1995 ◽  
Vol 384 ◽  
Author(s):  
P.A. Schroeder ◽  
P. Holody ◽  
R. Loloee ◽  
J. L. Duvail ◽  
A. BarthÉlemy ◽  
...  
Keyword(s):  
Field Dependence ◽  
Temperature Sensitivity ◽  
Magnetization Reversal ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Magnetic Nanostructures ◽  
Squid Magnetometer ◽  
Band Model ◽  
Superparamagnetic Behaviour ◽  
Discontinuous Nature

ABSTRACTEarly experiments to define oscillations in the CIP magnetoresistance (CIP-MR) of Ag/Co analogous to those for tcu < 5nm in Cu/Co were unsuccessful. The MR in this region was very small. Later experiments by Araki using thin (0.6nm ) Co layers produced much larger MRs and lead us to look at the MRs of similar samples more closely. We conclude that the large MR of such samples is associated with the discontinuous nature of the Co layers. The object of the present paper is to combine the high MR associated with the thin Co layers with the field dependence governed by the magnetization reversal in thick, and magnetically soft permalloy (Py) layers. We have measured the CIP-MR of sputtered samples of the [Co(O.4 nm)/Ag(tAg)/Py(tpy)/Ag(tAg)]×15 system with tAg ranging from 1.05 to 4nm and with tpy = 2 or 4nm. We obtain MRs at 4.2K as large as 35% in less than 100e with slopes as high as 5%/Oe. With CPP measurements slopes as high as 10%/Oe have been obtained. Squid magnetometer measurements indicate that, as the temperature increases, there is a crossover to superparamagnetic behaviour and a resulting gross deterioration of the MR slopes at room temperature. Efforts to increase the room temperature sensitivity are described. Detailed measurements of the CPP-MR of the [Co(0.4nm)/Ag(4nm)/Py(tpy)/Ag(4nm)]x20 series of multilayers are consistent with a two spin band model modified to take account of the granular nature of the Co.

Magnetic field dependence of voltage-current characteristics of Fe3O4 thin films at room temperature

2006 ◽  
Vol 88 (5) ◽  
pp. 052506 ◽  
Author(s):  
Kun Zhao ◽  
Jiafeng Feng ◽  
Yanhong Huang ◽  
Jian-gao Zhao ◽  
Huibin Lu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Field Dependence ◽  
Room Temperature ◽  
Magnetic Field Dependence ◽  
Current Characteristics

scholarly journals Fabrication of High Transparency Diamond-Like Carbon Film Coating on D263T Glass at Room Temperature as an Antireflection Layer

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chii-Ruey Lin ◽  
Hong-Ming Chang ◽  
Chien-Kuo Chang
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Carbon Film ◽  
Single Layer ◽  
Rf Magnetron Sputtering ◽  
Refraction Index ◽  
Diamond Powder ◽  
Water Repellent ◽  
Diamond Like Carbon ◽  
Visible Wavelengths

This study intends to deposit high transmittance diamond-like carbon (DLC) thin films on D263T glass substrate at room temperature via a diamond powder target using the radio frequency (RF) magnetron sputtering technique. Moreover, various process parameters were used to tune the properties of the thin films by using the Taguchi method. Experimental results show that the content of sp3bonded carbon decreases in accordance with the effect of the substrate temperature. In addition, the hardness of all as-deposited single-layer DLC films ranges from 13.2 to 22.5 GPa, and the RMS surface roughness was improved significantly with the decrease in sputtering pressure. The water repellent of the deposited DLC films improved significantly with the increase of the sp3content, and its contact angle was larger than that of the noncoated one by 1.45 times. Furthermore, the refraction index (n) of all as-deposited DLC films ranges from 1.95 to 2.1 atλ= 600 nm. These results demonstrate that the thickness increased as the reflectance increased. DLC film under an RF power of 150 W possesses high transmissive ability (>81%) and low average reflectance ability (<9.5%) in the visible wavelengths (atλ= 400–700 nm).

Giant Magnetoresistance in As-Sputter-Deposited Au/NiFe Multilayer Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
W. Y. Lee ◽  
G. Gorman ◽  
R. Savoy
Keyword(s):  
Thin Films ◽  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Multilayer Films ◽  
Antiferromagnetic Coupling ◽  
Multilayer Thin Films ◽  
Glass Substrates ◽  
Sputter Deposited

ABSTRACTGiant magnetoresistance with low saturation fields (Hs’s) is reported in Au and permalloy (Ni0.82Fe0.18) or Co-doped permalloy multilayer thin films as-deposited on Ta-overcoated Si and glass substrates. A ΔR/R as high as 4.0% with ≈25 Oe Hs was observed at 295 K for the film consisting of 10 layers of 24 Å Au/13 Å Ni0.82Fe0.18 deposited on a 3 Å Ta-overcoated glass at 50 °C. A Hs value as low as ≈20 Oe with a 15% smaller ΔR/R has been observed for the films with a thicker (e.g., 50 Å) Ta underlayer. Magnetic hysteresis loops of these films indicate the presence of antiferromagnetic exchange coupling between the Ni0.82Fe0.18 layers. This exchange coupling is much smaller for the multilayer films without the Ta underlayer, resulting in a 6x smaller ΔR/R and lOx larger Hs observed for these films. Results of x-ray diffraction analysis indicate stronger (111) texturing for the multilayer films with a Ta underlayer, consistent with the stronger antiferromagnetic coupling between the the Ni0.82Fe0.18 layers in the film. The addition of 2–10 % Co moderately increases the ΔR/R value, but also increases substantially the Hs (up to ≈200 Oe).

Stress in Sputtered Co90Fe10/Ag GMR Multilayers

1996 ◽  
Vol 436 ◽  
Author(s):  
J. D. Jarratt ◽  
V. R. Inturi ◽  
J. L. Weston ◽  
J. A. Barnard
Keyword(s):  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Multilayer Films ◽  
Antiferromagnetic Coupling ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
Individual Layer ◽  
X Ray ◽  
The Difference

AbstractStress, giant magnetoresistance (GMR), structure, and magnetic properties of sputtered (Co90Fe10X Å/Ag Y Å)×20 multilayer films have been investigated at room temperature where X ranges from 7.5 to 25 Å and Y from 10 to 60 Å. These films exhibit distinct GMR behaviors dependent on individual layer thicknesses, including layered granular-type GMR in CoFe 7.5 Å samples and ‘discontinuous’ GMR (DGMR) in CoFe 15 and 25 Å samples with Ag thicknesses over 30 Å. No antiferromagnetic coupling was observed. CoFe 10 Å samples act as a transition between GMR behaviors. Compressive stress decreases with increasing Ag thickness in the CoFe 7.5 Å samples. In the CoFe 15 and 25 Å samples the stress fluctuates similarly depending on Ag thickness. The difference in stress and MR behavior between the CoFe 7.5 Å and the 15 and 25 Å samples is thought to be due to incomplete CoFe layering in the CoFe 7.5 Å samples. In the CoFe 15 Å DGMR samples, high temperature annealing resulted in tensile stresses large enough to cause film detachment. X-ray diffraction reveals a strong (111) growth texture as well as satellite peaks from coherent layering. This (111) texture is also evidenced by patterns with hexagonal symmetry formed by the detached films.

Electrodeposited Magnetic Multilayers

1996 ◽  
Vol 451 ◽  
Author(s):  
W. Schwarzacher ◽  
M. Alper ◽  
R. Hart ◽  
G. Nabiyouni ◽  
I. Bakonyi ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Giant Magnetoresistance ◽  
Single Layer ◽  
Multilayer Films ◽  
Magnetic Multilayers ◽  
Magnetic Multilayer ◽  
Cu Film ◽  
Magnetic Metal ◽  
Cu Foil

ABSTRACTElectrodeposited magnetic multilayer films consisting of alternating layers of a ferromagnetic and a non-magnetic metal may exhibit giant magnetoresistance (GMR), but the effect is very sensitive to whether deposition is carried out under potentiostatic or galvanostatic control, and the choice of substrate. The texture of Co-Ni-Cu/Cu superlattices grown on polycrystalline (100)-textured Cu plates and (HO)-textured Cu foil under potentiostatic control depended on that of the substrate, while comparable superlattices grown under galvanostatic control had a predominantly (111) texture. The films grown under galvanostatic control generally exhibit AMR or smaller GMR. The magnetic and magnetotransport properties of Co-Ni-Cu/Cu superlattices and a single-layer Co-Ni-Cu film electrodeposited directly onto n-GaAs (100) are also described, and evidence is presented for an in-plane magnetic anisotropy in these samples.

Quantitative adhesion measures of multilayer films: Part I. Indentation mechanics

1999 ◽  
Vol 14 (7) ◽  
pp. 3007-3018 ◽  
Author(s):  
Michael D. Kriese ◽  
William W. Gerberich ◽  
Neville R. Moody
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Original Film ◽  
Driving Force ◽  
Experimental Situation ◽  
Finite Thickness ◽  
Single Layer ◽  
Companion Paper ◽  
Multilayer Films

The mechanics for calculating the quantitative driving force of indentation-induced delamination of thin-film multilayers is presented. The solution is based on the mechanics developed by Marshall and Evans [D.B. Marshall and A.G. Evans, J. Appl. Phys. 56, 2632 (1984).] and extended to the general case of a multilayer by use of standard bending and thin-plate analyses. Presented and discussed are the specific solutions for the bilayer case that show that in the limit of zero thickness of either layer, the solution converges to the single-layer case. In the range of finite thickness, the presence of the superlayer increases the driving force relative to that possible for the original film alone and can be optimized to the experimental situation by proper choice of thickness, elastic constants, and residual stress. The companion paper “Quantitative adhesion measures of multilayer films: Part II. Indentation of W/Cu, W/W, Cr/W” discusses experimental results with copper, tungsten, and chromium thin films.

Giant magnetoresistance and superparamagnetism in DyxFe100-x nanogranular magnetic thin films at room temperature

2016 ◽  
Author(s):  
Laxman Mekala ◽  
Muhammed Shameem P. V. ◽  
Dushyanth Singh ◽  
M. Senthil Kumar
Keyword(s):  
Thin Films ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Magnetic Thin Films

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

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