Giant Magnetoresistance Studies of NiFe-Based Spin-Valve Multilayers

1994 ◽  
Vol 343 ◽  
Author(s):  
Chien-Li Lin ◽  
John M. Sivertsen ◽  
Jack H. Judy
Keyword(s):  
Magnetic Field ◽  
Thermal Stability ◽  
Magnetic Properties ◽  
Multilayer Structure ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Spin Valve ◽  
Vibrating Sample Magnetometer ◽  
Recording Head ◽  
Annealing Experiments

ABSTRACTThe giant magnetoresistance in FeMn exchange-biased NiFe-based multilayer spin-valve structures prepared by rf-diode sputtering technique were studied. Experiments were performed on samples with different thicknesses of each layer in these multilayers. The magnetic properties were measured using a vibrating sample magnetometer and the giant magnetoresistance was measured using an in-line four-point magnetoresistance probe. A magnetoresistance of 6.5% in a magnetic field of less than 15 Oe was obtained in a Cu(30Å)/FeMn(150Å)/NiFe(50Å)/Co(15Å)/ Cu(20Å)/Co(15Å)/NiFe(60Å) multilayer structure at room temperature. Annealing experiments of these multilayers were performed to study the thermal stability during the recording head fabrication processes. No degradation in the magnetoresistance has been found for annealing these films at 230°C up to four hours.

Giant Magnetoresistance in FeMn/NiCoFe/Cu/NiCoFe Spin Valve Prepared by Opposed Target Magnetron Sputtering

2014 ◽  
Vol 979 ◽  
pp. 85-89 ◽  
Author(s):  
Ramli ◽  
Euis Sustini ◽  
Nurlaela Rauf ◽  
Mitra Djamal
Keyword(s):  
Magnetron Sputtering ◽  
Layer Thickness ◽  
Coercive Field ◽  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Spin Valve ◽  
Ferromagnetic Layer ◽  
Vibrating Sample Magnetometer ◽  
Magnetoresistance Ratio ◽  
Scanning Electron

The giant magnetoresistance (GMR) effect in FeMn/NiCoFe/Cu/NiCoFe spin valve prepared by dc opposed target magnetron sputtering is reported. The spin valve thin films are characterized by Scanning Electron Microscopy (SEM), Vibrating Sample Magnetometer (VSM) and magnetoresistance ratio measurements. All measurements are performed in room temperature. The inserted 45 mm thickness FeMn layer to the NiCoFe/Cu/NiCoFe system can increase the GMR ratio up to 32.5%. The coercive field to be increased is compared with different FeMn layer thickness. Furthermore, the coercive field (Hc) decreases with increasing FeMn layer thickness. Magnitude of coercive field is 0.1 T, 0.09 T and 0.08 T for FeMn layer thickness is 30 nm, 45 nm and 60 nm, respectively. The FeMn layer is used to lock the magnetization in the ferromagnetic layer through the exchange anisotropy. This paper will describe the development of a GMR spin valve and its magnetic properties.

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.

Martensitic Transformation and Mechanical Properties of Fe-Doped Ni54Mn21Ga25 Alloys

2011 ◽  
Vol 687 ◽  
pp. 500-504
Author(s):  
S. X. Xue ◽  
S.S. Feng ◽  
P. Y. Cai ◽  
Q T Li ◽  
H. B. Wang
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Magnetic Properties ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Directional Solidification ◽  
Transformation Temperature ◽  
Room Temperature ◽  
Martensitic Transformation Temperature ◽  
Polycrystalline Alloys

Ni54Mn21-xFexGa25（x=0,1,3,5,7,9）polycrystalline alloys were prepared by the technique of directional solidification and the effect of substituting Fe for Mn on the martensitic transformation and mechanical properties of the alloys was analyzed. It was found that the Curie temperature increased with increasing substitution while the martensitic transformation temperature decreased. The Fe-doped Ni54Mn21Ga25 alloys exhibit excellent magnetic properties at room temperature; the typical Ni54Mn20Fe1Ga25 alloy shows a large magnetic-induced-strain of -1040 ppm at a magnetic field of 4000 Oe.

Thermal Stability of Magnetic Properties in Dehydrogenated Triarylmethane Resins

1989 ◽  
Vol 173 ◽  
Author(s):  
Michiya Otani ◽  
Sugio Otani
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
The Stability ◽  
Thermal Stability Of

ABSTRACTThe stability of the magnetic properties of dehydrogenated triaryl-methane resins was investigated both at room temperature and at elevated temperatures. A magnetic property different from that reported in a previous paper was found in the course of studying the reproducibility of synthesis. This new property was examined through a mechanical response of the resins to a set of permanent magnets.

Magnetic and magnetoresistive properties of nanocomposites based on Co and SiO

2019 ◽  
Vol 33 (12) ◽  
pp. 1950113 ◽  
Author(s):  
I. M. Pazukha ◽  
Y. O. Shkurdoda ◽  
A. M. Chornous ◽  
L. V. Dekhtyaruk
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Process ◽  
Anisotropic Character ◽  
Co Concentration ◽  
Beam Method ◽  
The Magnetic Field ◽  
Film Nanocomposites

A series of thin-film nanocomposites based on ferromagnetic metal Co and insulator SiO were prepared using an electron-beam method. The magnetoresistive and magnetic properties of these structures deposited at room temperature and then annealed to 700 K were investigated. The results showed that at the Co concentration 40 [Formula: see text]x [Formula: see text] 60 at.%, thin-film nanocomposites exhibit magnetoresistance (MR) that is conditional on spin-dependent tunnelling of electrons. This range of concentrations corresponds to the prepercolation area according to the magnetic investigations. For samples with x [Formula: see text] 70 at.%, the anisotropic character of MR peculiar to the homogeneous ferromagnetic materials appears. According to the magnetic properties study, this range of concentrations corresponds to the area after transition through the percolation threshold. The annealing process in temperature range from 300 K to 700 K in the magnetic field slightly influenced the magnetoresistive properties of the thin-film nanocomposites based on Co and SiO for all range of concentrations.

Towards a Room Temperature Organic Spin Valve: Structural, Magnetic and Transport Properties of Fe3O4/PTCTE/Co Devices

2011 ◽  
Vol 1359 ◽  
Author(s):  
Mathieu Palosse ◽  
Elena Bedel-Pereira ◽  
François Olivié ◽  
Isabelle Séguy ◽  
Christina Villeneuve ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Current Distribution ◽  
Morphological Study ◽  
Room Temperature ◽  
Spin Valve ◽  
Vibrating Sample Magnetometer ◽  
Force Microscopy ◽  
Dc Sputtering ◽  
Ferromagnetic Electrodes ◽  
Atomic Force

ABSTRACTThis paper describes first steps in preparation of an organic spin valve based on a perylene derivative (PTCTE) sandwiched between magnetite (Fe3O4) and cobalt (Co) ferromagnetic electrodes. MgO(001)/Fe3O4/PTCTE (450 nm)/Co devices were prepared with different Co soft deposition methods: off-axis dc-sputtering or Joule evaporation. Vibrating Sample Magnetometer (VSM) studies of the Fe3O4/PTCTE/Co stacks evidence spin valve behavior with magnetically uncoupled electrodes. These results are correlated with a morphological study by atomic force microscopy (AFM) of each layer and tunneling AFM (TUNA) for the investigation of inhomogeneity of current distribution in the devices. Finally, macroscopic I-V characteristics performed on the same devices will be presented and compared with TUNA results.

GMR and Structure in Sputtered Co90Fe10/Ag Multilayers

1995 ◽  
Vol 403 ◽  
Author(s):  
J. D. Jarratt ◽  
J. A. Barnard
Keyword(s):  
Magnetic Properties ◽  
Multilayer Structure ◽  
Giant Magnetoresistance ◽  
Multilayer Films ◽  
X Ray Diffraction ◽  
Individual Layer ◽  
X Ray ◽  
The Individual

AbstractGiant magnetoresistance (GMR), structure, and magnetic properties of sputtered (Co90Fe10 X Å/Ag Y Å) multilayer films have been investigated. Distinct GMR behaviors including granulartype (GGMR) and ‘discontinuous’ (DGMR) are observed which are strongly dependent on the individual CoFe and Ag layer thicknesses; however, standard multilayer GMR and the associated antiferromagnetic (AFM) coupling is absent. The multilayer structure, individual layer thicknesses, and growth texture were investigated using high and low angle x-ray diffraction (HXRD & LXRD).

Development of a Novel Vibrating Sample Magnetometer

2007 ◽  
Vol 537-538 ◽  
pp. 413-418 ◽  
Author(s):  
István Mészáros
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Materials Science ◽  
Science Laboratory ◽  
Vibrating Sample Magnetometer ◽  
Hard Magnetic Materials ◽  
Measuring Device ◽  
Parallel Motion ◽  
New Type

A new type of vibrating sample magnetometer (VSM) was designed for measuring the magnetic properties of soft and hard magnetic materials is described. The developed instrument differs from the traditional Foner type because in our system the motion of the specimen is parallel with the lines of the external magnetic field. Therefore, this instrument can be called parallel motion vibrating sample magnetometer (PMVSM). The special vibrating system contains a vibrating rod which holds the specimen. This arrangement can make the sample replacement and positioning fast and convenient. Because of the versatility of the PMVSM instrument it could be a useful measuring device for materials science laboratory and educational purposes as well.

Preparation and Characterization of Sro-Na2O-Fe2O3-P2O5-SiO2 Ferrimagnetic Glass-Ceramics for Hyperthermia Application

2012 ◽  
Vol 581-582 ◽  
pp. 457-462
Author(s):  
Jian An Liu ◽  
Xue Na Yang ◽  
Mei Mei Zhang ◽  
Wen He
Keyword(s):  
Aqueous Solution ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Glass Ceramic ◽  
Room Temperature ◽  
Glass Ceramics ◽  
Vibrating Sample Magnetometer ◽  
Heat Treated ◽  
Molecular Scale

The ferrimagnetic glass-ceramic based on SrO-Na2O-Fe2O3-P2O5-SiO2 system was prepared for hyperthermia application using aqueous aolution-melt method. Using the aqueous solution solvent evaporation, we obtained the molecular-scale homogenously glass precursor. The precursor was completely melted in a lidded platinum crucible placed in an electric furnace at 1480°C for 1h and then annealed in a furnace at 550°C for 40min.The annealed glasses were heat treated at 1050°C for 2h to obtain the glass-ceramics. The crystallization of the glass systems with different component has been systematically investigated by using XRD. Room temperature magnetic property of the samples were investigated using a Vibrating Sample Magnetometer(VSM). The evolution of magnetic properties in these glasses as a function of P2O5 quality concentration was discussed.

Sign in / Sign up

Export Citation Format

Share Document