Exchange Coupling and Giant Magnetoresistance in Electrodeposited Co/Cu Multilayers

1997 ◽  
Vol 475 ◽  
Author(s):  
A. Dinia ◽  
K. Rahmouni ◽  
G. Schmerber ◽  
H. El Fanity ◽  
M. Bouanani ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Magnetoresistance Effect ◽  
X Ray ◽  
Resistivity Measurements ◽  
Fee Structure ◽  
Giant Magnetoresistance Effect ◽  
Spacer Layer

ABSTRACTWe present the results of the transport and magnetization measurements of electrodeposited Co/Cu multilayers grown in a single electrolyte based on C0SO4, H3BO3 and CuSO4. The samples are deposited on glass substrate covered by a 500 Å thick Cu buffer layer. X-ray diffraction performed on the samples shows fee structure of both Co and Cu layers with preferential (111) orientation. Resistivity measurements show a giant magnetoresistance effect of about 4% at room temperature for multilayers with Co and Cu thickness between 4 nm ≤ tco ≤ 6 nm and 3 nm ≤ tcu ≤4 nm respectively. For Co thickness tCo ≤ 15 nm, the magnetoresistance completely vanishes indicating that there is no more continuous Co layer. The indirect antiferromagnetic exchange coupling between magnetic Co layers is relatively large for 4 nm thick Cu spacer layer and gives rise to a temperature dependence of about 30% between room temperature and 4.2 K.

Giant Magnetoresistance in Annealed Fe/Cr Multilayers

1993 ◽  
Vol 313 ◽  
Author(s):  
Noa More Rensing ◽  
Bruce M. Clemens
Keyword(s):  
Giant Magnetoresistance ◽  
Structural Effect ◽  
Magnetic Effect ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
Magnetoresistance Effect ◽  
X Ray ◽  
Giant Magnetoresistance Effect ◽  
Higher Temperature ◽  
Spin Dependent Scattering

ABSTRACTThe giant magnetoresistance effect in antiferromagnetically coupled Fe/Cr Multilayers has been attributed to spin dependent scattering at the interfaces between the constituents. One possible source of this spin dependent scattering is chromium impurities in the iron layers due to intermixing at the interfaces. Annealing the films can promote the diffusion of the components, increasing the impurity concentration and therefore the Magnetoresistance. For this study Fe/Cr Multilayers were annealed at several temperatures and for several durations. Annealing at moderate temperatures (∼ 350°C) increases the Magnetoresistance, while higher temperature anneals (∼ 600°C) cause the magnetoresistance to disappear completely. Long anneals at 330°C (> 100 hours) also reduce the Magnetoresistance. VSM Measurements indicate that the antiferromagnetic coupling is reduced in the annealed samples but show no evidence of Magnetically “dead” alloy layers. Low angle X-ray diffraction indicates that the structural effect of annealing is very subtle in comparison to the significant magnetic effect.

Evolution of crystal structure of dual layered molecular conductor (ET)4ZnBr4(C6H4Cl2) with temperature

CrystEngComm ◽  
2021 ◽  
Author(s):  
Gennady V. Shilov ◽  
Elena I. Zhilyaeva ◽  
Sergey M. Aldoshin ◽  
Alexandra M Flakina ◽  
Rustem B. Lyubovskii ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Single Crystal ◽  
Room Temperature ◽  
Organic Conductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Molecular Conductor ◽  
Abrupt Changes

Electrical resistivity measurements of a dual layered organic conductor (ET)4ZnBr4(1,2-C6H4Cl2) above room temperature show abrupt changes in resistivity at 320 K. Single-crystal X-ray diffraction studies in the 100-350 K range...

Giant Magnetoresistance and Structure of Phase-Segregated Epitaxial Metals

1993 ◽  
Vol 313 ◽  
Author(s):  
R.F. Marks ◽  
R.F.C. Farrow ◽  
G.R. Harp ◽  
S.S.P. Parkin ◽  
T.A. Rabedeau ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Grazing Incidence ◽  
Film Structure ◽  
X Ray ◽  
Spacing Effects ◽  
X Ray Scattering ◽  
Technological Potential ◽  
First Time

ABSTRACTGiant Magnetoresistance, GMR, in thin metal films elicits attention due to its technological potential as well as its relevance to theory of exchange coupling. Epitaxial, phase-segregated ferromagnet/paramagnet Mixtures have been grown by UHV evaporation. Such films show spontaneous formation of ferromagnetic clusters, leading to large values of GMR (40% at room temperature) as grown. The growth of Co-Cu, Co-Ag, Fe-Ag and Permalloy-Ag films are described. Structural analysis by grazing-incidence small angle X-ray scattering (GISAXS) provides a measure of cluster size and characteristic spacing. Effects of growth temperature and subsequent annealing on GMR and film structure are described. Preliminary results of TEM examination of (001) Fe-Ag and Co-Ag granular films are presented for the first time.

FERROMAGNETISM IN Fe-DOPED ZnO THIN FILMS

2009 ◽  
Vol 23 (06) ◽  
pp. 815-824 ◽  
Author(s):  
R. B. ZHAO ◽  
D. L. HOU ◽  
Y. Y. WEI ◽  
Z. Z. ZHOU ◽  
C. F. PAN ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Exchange Coupling ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Si Substrates ◽  
Fe Ions

Zn 1-x Fe x O (x = 0.04, 0.06, 0.08, 0.10, 0.12) thin films were grown on Si substrates using reactive magnetron sputtering. X-ray diffraction analyses show that the samples have wurtzite structures with the c-axis orientation. X-ray photoelectron spectroscopy results indicate that the Fe ions are in a +2 charge state in the films. Magnetization measurements indicate that room temperature ferromagnetism is present in films annealed in vacuum while films annealed in air were non-magnetic. The presence of oxygen vacancies in these films may mediate exchange coupling of the dopant ions, resulting in room temperature ferromagnetism.

EFFECT OF γ RADIATION ON SOME PHYSICAL PROPERTIES OF THE SPINEL FERRITE SYSTEM Ni0.65Zn0.35CuxFe2−xO4

1994 ◽  
Vol 08 (28) ◽  
pp. 1781-1790 ◽  
Author(s):  
F.S. TERRA
Keyword(s):  
Electrical Resistivity ◽  
Room Temperature ◽  
Spinel Ferrite ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Γ Radiation ◽  
X Ray ◽  
Resistivity Measurements ◽  
Dta Analysis ◽  
Ferrite System

X-ray diffraction analysis, electrical resistivity measurements at room temperature, and differential thermal analysis (DTA) were carried out for γ-irradiated Ni 0.65 Zn 0.35 Cu xFe2−x O 4 spinel ferrite samples. It was found that the lattice parameter decreased, i.e. the theoretical density increased, while the electrical resistivity decreased. From the DTA analysis there is an endothermic peak at 100–130º C due to internal stress created by γ radiations as a result of lattice defects formation.

MICROSTRUCTURE OF FeCo–Cu NANOGRANULAR FILMS WITH GIANT MAGNETORESISTANCE

2007 ◽  
Vol 21 (20) ◽  
pp. 1297-1305
Author(s):  
CHANGZHENG WANG ◽  
PEIMING ZHANG ◽  
YIQING ZHANG ◽  
XIAOGUANG XIAO ◽  
YONGHUA RONG ◽  
...  
Keyword(s):  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Coherent Interface ◽  
X Ray ◽  
Cu Films ◽  
Transmission Electron ◽  
The Relationship ◽  
Fcc Structure

A series of ( Fe 50 Co 50)x Cu 1-x granular films were prepared using a magnetron-controlled sputtering system. The microstructure and giant magnetoresistance of FeCo–Cu films deposited at room temperature and then annealed at various temperatures were investigated through X-ray diffraction, transmission electron microscope and conventional four-probes method under room temperature, respectively. The results revealed that FeCo–Cu films consisted of fine FeCo granules uniformly dispersed in the Cu matrix and formed fcc structure. Meanwhile the Cu (111) interplaner lattice spacing decreased with increasing magnetic volume fraction (x) due to the presence of the metal coherent interface strains and FeCo–Cu alloying. Upon varying the magnetic volume fraction (x), the giant magnetoresistance of as-deposited FeCo–Cu films reached a maximum of about 0.7% at the volume fraction of 31%, corresponding to the fact that the giant magnetoresistance has a non-monotonic relationship with the granule size. In addition, the relationship between the full width at half maximum (FWHM) or the sensitivity of the giant magnetoresistance and the volume fraction are discussed in detail.

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.

Microcharacterization of liquid delivery metalorganic chemical vapor deposition processed thin film materials exhibiting giant magnetoresistance

1999 ◽  
Vol 14 (5) ◽  
pp. 2007-2011 ◽  
Author(s):  
M. L. Weaver ◽  
L. P. M. Brandao ◽  
H. Garmestani ◽  
E. S. Gillman ◽  
K. H. Dahmen ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metalorganic Chemical ◽  
Liquid Delivery

Thin films of La0.6Ca0.4MnO3 (LCMO) have been produced on (001) oriented LaAlO3 (LAO) and yttrium-stabilized zirconia (YSZ) substrates by liquid-delivery metalorganic chemical vapor deposition (LD-MOCVD). X-ray diffraction (XRD) analyses showed that the films were epitaxially grown on LAO substrates and were monocrystalline at a thickness of less than 500 Å. At a thickness of greater than 500 Å, the films became polycrystalline but maintained their high texture (preferred crystalline orientation). Films grown on YSZ were always polycrystalline but were also highly oriented. Regardless of the substrate, the 1500 Å thick polycrystalline films exhibited substantially significant magnetoresistance ratios even above room temperature.

Cerium Doped Bismuth Based High Tc Superconductor: Synthesis and Study of Superconducting Properties

2012 ◽  
Vol 510-511 ◽  
pp. 75-79
Author(s):  
M. Mubeen ◽  
M. Anis-ur-Rehman
Keyword(s):  
Chemical Method ◽  
Room Temperature ◽  
Dc Resistivity ◽  
Ceramic Superconductor ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Resistivity Measurements ◽  
Wet Chemical

High-Tcsuperconductivity has been an emerging field for researchers since its discovery. Bismith based superconductors commonly called BSCCO have great importance among the superconducting family. It is divided into three phases among them 2223 phase is highly studied in order to investigate its superconducting properties by substitution of different elements. We have studied the substitution of cerium (Ce) on calcium site of bismuth based Bi (Pb)Sr (Ba)-2223 high-Tcsuperconductor. The nominal compositions of Bi1.6Pb0.4Sr1.6Ba0.4(Ca1-xCex)2Cu3Oxceramic superconductor were prepared by wet chemical method. Stoichiometric amounts of Bi2O3, PbO, Sr (NO3)2, BaCO3, CaCO3, CuO and CeO2were used as starting materials. Structural analysis was done by X-ray diffraction (XRD) at room temperature and different parameters were calculated. DC resistivity measurements for the transition temperature of synthesized superconducting samples were taken by the standard four-probe method, apparatus for which was developed in our laboratory. It is observed that with the substitution of cerium on calcium site the single high-Tc2223 phase is obtained.

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