Giant Magnetoresistance in Co/Ag Multilayers

1993 ◽  
Vol 313 ◽  
Author(s):  
M. Tan ◽  
J. A. Barnard ◽  
M. R. Parker ◽  
D. Seale
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Layered Structure ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Antiferromagnetic Coupling ◽  
High Angle ◽  
X Ray ◽  
Field Sensitivity

ABSTRACTThe Magnetoresistance (MR), Magnetic properties, and crystal structure of dc magnetron sputtered CO/Ag periodic multilayers have been investigated. The Co layer thickness was fixed at -30 Å while the thickness of the Ag layer was systematically varied. ‘Giant’ magnetoresistance was observed. The MR ratio has been found to decline monotonically with increasing Ag thickness in the range 30 Å to 107 Å. Although the maximum room temperature MR ratio is a Modest 4.78%, a more technologically significant measurement of field sensitivity (MR ratio/FWHM of the MR vs. H peak) is a promising 0.1%/Oe at its best. The effect of the number of bilayer units has also been examined and no substantial differences were noted between multilayers containing 8, 9, and 10 bilayer units. Coercivities as determined by both magnetometer and the splitting of the MR peaks are in agreement and increase from 25 to 38 Oe with increasing Ag thickness. Evidence for antiferromagnetic coupling is apparent in the hysteresis loops. High angle X-ray diffractometry (HXRD) in the θ-2θ mode revealed a strong Ag (111) texture in the film, with satellite peaks indicating a layered structure. Low angle XRD (LXRD) also yielded broad superlattice peaks in all samples at least to the second order.

scholarly journals Structural and Magnetic Properties of Ni0.8Fe0.2/Ti Nanoscale Multilayers

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 780 ◽  
Author(s):  
Ricardo López Antón ◽  
Juan A. González ◽  
Juan P. Andrés ◽  
Andrei V. Svalov ◽  
Galina V. Kurlyandskaya
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Layered Structure ◽  
Magnetic Measurements ◽  
Hysteresis Loops ◽  
Multilayered Structures ◽  
X Ray ◽  
Structural And Magnetic Properties

The influence of the thickness of the Ni0.8Fe0.2 (Permalloy, Py) layers on the structural and magnetic properties of magnetron sputtered Py/Ti multilayers was studied. The thickness of the Py layers was varied in the interval of 8 to 30 Å. X-ray reflectivity scans evidence the existence of a well-defined layered structure in all the samples considered, but also the presence of a complex intermixed interface. The shape of both the temperature dependence of magnetization and the hysteresis loops of the multilayered structures depends strongly on Py thickness. Magnetic and reflectivity measurements were comparatively analyzed in order to better understand the structure of the samples, and specifically, their interfaces. In particular, the presence of small superparamagnetic Py at the interfaces of the samples, especially evident in the samples with the thinnest Py layers, seems confirmed by the magnetic measurements, agreeing well with the reflectivity results.

Influence of Magnetic Field on Magnetic Properties of Electrodeposited Co-Ni-P Nanowires

2014 ◽  
Vol 24 (3S1) ◽  
pp. 90-94 ◽  
Author(s):  
Le Tuan Tu ◽  
Luu Van Thiem ◽  
Pham Duc Thang
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Structure And Morphology ◽  
The Magnetic Field

The magnetic properties in Co-Ni-P nanowires arrays with diameter of 200 nm were investigated. All the samples were prepared by electrodeposition method with pH of 5.5 and at room temperature. During the deposition, a magnetic field in range of 0 - 750 Oe was applied parallel to the wires axis. The crystalline structure and morphology of the samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The hysteresis loops were measured at room temperature using vibrating sample magnetometry (VSM). The mixture of hcp phases of the Co-Ni-P based nanowires has been indicated by the XRD pattern. The obtained results show that with 750 Oe magnetic field applied during deposition we can obtain maximum coercivity value (2180 Oe). The \(M_{r}/M_{s}\) ratio was rapid increased when the magnetic field changed from 0 Oe to 750 Oe.

Doping Strategies of Bi (Ti0.5Ni0.5)O3 for Increased Performance in BiFeO3

2014 ◽  
Vol 1004-1005 ◽  
pp. 358-361
Author(s):  
Zheng Zheng Ma ◽  
Jian Qing Li ◽  
Zi Peng Chen ◽  
Xiao Jun Hu
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Magnetic Properties ◽  
Solid Solutions ◽  
Perovskite Structure ◽  
Room Temperature ◽  
Ferroelectric Properties ◽  
Hysteresis Loops ◽  
Space Group ◽  
Substituted 1

Investigation of crystal structure, dielectric, magnetic and local ferroelectric properties of the diamagnetically substituted (1-x)BiFeO3-xBi (Ti0.5Ni0.5)O3solid solutions samples have been carried out. The solid solutions have been found to possess a rhombohedrally distorted perovskite structure described by the space group R3c. Compared with pure BiFeO3compound, both ferroelectric and magnetic properties are much improved by solid solution with Bi (Ti0.5Ni0.5)O3with saturation hysteresis loops observed. Among all the samples, thex=0.1 samples shows the optimal ferromagnetism with Mr~0.56531emμ/g and the optimal ferroelectricity with Pr~5.767μC/cm2 at room temperature.

A three-dimensional cyanide-bridged heterometallic coordination polymer: poly[[diacetonitrilediaqua[μ2-3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine-κ4N1,N6:N3,N4]tetra-μ-cyanido-tetracyanidodimanganese(II)molybdate(IV)] dihydrate]

2014 ◽  
Vol 70 (11) ◽  
pp. 1029-1032 ◽  
Author(s):  
Xiao-Juan Xu
Keyword(s):  
Magnetic Properties ◽  
Ir Spectroscopy ◽  
Coordination Polymer ◽  
Elemental Analysis ◽  
Room Temperature ◽  
Three Dimensional ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Investigation

A metal coordination polymer, {[Mn2Mo(CN)8(C12H8N6)(CH3CN)2(H2O)2]·2H2O}n, has been synthesized by the reaction of Mn(ClO4)2·6H2O with 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine (bptz) and (Bu3N)3[Mo(CN)8] at room temperature. The polymer was characterized by IR spectroscopy, elemental analysis and X-ray diffraction, and the magnetic properties were also investigated. The X-ray diffraction analysis reveals that the compound is a new three-dimensional coordination polymer with a PtS-type network. Magnetic investigation shows antiferromagnetic coupling between adjacent Mn2+cations.

Dielectric, Piezoelectric and Magnetic Properties of Ferroelectromagnet Pb(Fe1/3Nb2/3)O3(PFN) Ceramics

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3732-3737 ◽  
Author(s):  
Jin. T. Wang ◽  
Marx K. Mbonye ◽  
Cheng Zhang
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Magnetic Properties ◽  
Transition Temperature ◽  
Dielectric Loss ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Dielectric Constant ◽  
Piezoelectric Strain

Ferroelecromagnet Pb ( Fe 1/3 Nb 2/3) O 3 has been synthesized and its crystal structure and dielectric, electrostrictive and magnetic properties have been investigated. The structure of PFN ceramics examined by X-ray diffraction was found perovskite-like. The dielectric constant and dielectric loss as a function of temperature at different frequencies was measured. A para-ferroelectric transition at a temperature of 403 K was found and the maximum dielectric constant at a frequency of 500 Hz at the transition temperature is as high as 9050. The piezoelectric strain at room temperature was examined. The magnetization measurements as a function of temperature in the temperature region from room temperature to 648 K with different applied magnetic fields revealed that the compound is antiferromagnetic.

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.

Synthesis, crystal structure and magnetic characterization of a cyanide-bridged Mo–Ni nanosized molecular wheel

2015 ◽  
Vol 70 (8) ◽  
pp. 527-531 ◽  
Author(s):  
Daopeng Zhang ◽  
Lingqian Kong ◽  
Hongyan Zhang ◽  
Ping Wang
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Ir Spectroscopy ◽  
Structure Determination ◽  
Building Blocks ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
Magnetic Characterization ◽  
X Ray

AbstractBy using K4[Mo(CN)8] and [Ni(L)(H2O)2][ClO4]2 as reagents (L = 2,12-dimethyl-3,7,11,17-tetraazabicyclo [11.3.1]heptadeca-1(17),13,15-triene), a new cyanide-bridged Mo–Ni complex containing the building blocks [Ni(H2O)(L)]2+ and [Ni(L)]2+ bridged by [Mo(CN)8]4− units has been obtained. The complex with the formula {[Ni(H2O)(L)][Ni(L)][Mo(CN)8]}6 · 36H2O · 2CH3OH (1) was characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The structure determination reveals an octadecanuclear cluster in the form of a 36-membered macrocycle, in which the largest intramolecular W···W and Ni···Ni distances are 16.5 and 14.4 Å, respectively, indicating that complex 1 is a nanosized molecular wheel. Investigation of its magnetic properties has shown weak antiferromagnetic coupling between the adjacent Ni(II) ions bridged by the diamagnetic [Mo(CN)8]4− ions.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Effect of Annealing temperature on the Structural and Magnetic Properties of TbxY3-xFe5O12(x = 0.0, 1.0, 2.0) Thin Films Prepared by Sol-Gel Process

2012 ◽  
Vol 501 ◽  
pp. 236-241 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah ◽  
Ramadan E. Shaiboub
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Garnet Phase ◽  
Sol Gel Process ◽  
Amorphous Structures

Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

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