Giant magnetoresistance at room temperature achieved in the ferromagnetic phase of powder La0.5Sr0.5MnO3

The creation of a giant magnetoresistance (GMR) effect in a spinodally decomposed and deformed Cu-20% Ni-20% Fe alloy is reported. The alloy is processed to contain a locally multilayered superlattice-like structure with alternating ferromagnetic and nonmagnetic layers with a size scale of 10-20 Å. The microstructural modification produced a dramatic improvement in room-temperature magnetoresistance ratio from ∼0.6 to ∼5%. The observed magnetoresistance is most likely related to the spin-dependent scattering at the two-phase interface and in the ferromagnetic phase, although the exact mechanism involved may be qualitatively different from the usual GMR picture. A rather unusual temperature-dependence of magnetoresistance ratio, i.e., the room-temperature value being greater than that at 4.2 K, was found.

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Giant magnetoresistance in La1−xSrxMnOzfilms near room temperature

Applied Physics Letters ◽

10.1063/1.112808 ◽

1994 ◽

Vol 65 (16) ◽

pp. 2108-2110 ◽

Cited By ~ 422

Author(s):

H. L. Ju ◽

C. Kwon ◽

Qi Li ◽

R. L. Greene ◽

T. Venkatesan

Keyword(s):

Giant Magnetoresistance ◽

Room Temperature

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Stable room-temperature ferromagnetic phase at the FeRh(100) surface

Scientific Reports ◽

10.1038/srep22383 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 27

Author(s):

Federico Pressacco ◽

Vojtěch Uhlίř ◽

Matteo Gatti ◽

Azzedine Bendounan ◽

Eric E. Fullerton ◽

...

Keyword(s):

Room Temperature ◽

Ferromagnetic Phase

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Hyperfine interaction and some thermomagnetic properties of amorphous and partially crystallized Fe70−xMxMo5Cr4Nb6B15 (M = Co or Ni, x = 0 or 10) alloys

Nukleonika ◽

10.1515/nuka-2015-0025 ◽

2015 ◽

Vol 60 (1) ◽

pp. 121-126

Author(s):

Jakub Rzącki ◽

Jan Świerczek ◽

Mariusz Hasiak ◽

Jacek Olszewski ◽

Józef Zbroszczyk ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Hyperfine Interaction ◽

Magnetic Structure ◽

Curie Point ◽

Room Temperature ◽

Ferromagnetic Phase ◽

X Ray ◽

Transmission Electron ◽

Thermomagnetic Properties

Abstract As revealed by Mössbauer spectroscopy, replacement of 10 at.% of iron in the amorphous Fe70Mo5Cr4Nb6B15 alloy by cobalt or nickel has no effect on the magnetic structure in the vicinity of room temperature, although the Curie point moves from 190 K towards ambient one. In the early stages of crystallization, the paramagnetic crystalline Cr12Fe36Mo10 phase appears before α-Fe or α-FeCo are formed, as is confirmed by X-ray diffractometry and transmission electron microscopy. Creation of the crystalline Cr12Fe36Mo10 phase is accompanied by the amorphous ferromagnetic phase formation at the expense of amorphous paramagnetic one.

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Thermal Characterization of Cu/CoFe Multilayer for Giant Magnetoresistive (GMR) Head Applications

Heat Transfer, Volume 2 ◽

10.1115/imece2004-62113 ◽

2004 ◽

Cited By ~ 1

Author(s):

Y. Yang ◽

M. Asheghi

Keyword(s):

Giant Magnetoresistance ◽

Room Temperature ◽

Boltzmann Transport Equation ◽

Thermal Characterization ◽

Disk Drive ◽

Boltzmann Transport ◽

Self Heating ◽

Superlattice Structure ◽

Metallic Ferromagnet

Giant Magnetoresistance (GMR) head technology is one of the latest advancement in hard disk drive (HDD) storage industry. The GMR head superlattice structure consists of alternating layers of extremely thin metallic ferromagnet and paramagnet films. A large decrease in the resistivity from antiparallel to parallel alignment of the film magnetizations can be observed, known as giant magnetoresistance (GMR) effect. The present work characterizes the in-plane electrical and thermal conductivities of Cu/CoFe GMR multilayer structure in the temperature range of 50 K to 340 K using Joule-heating and electrical resistance thermometry in suspended bridges. The thermal conductivity of the GMR layer monotonously increased from 25 Wm−1K−1 (at 55 K) to nearly 50 Wm−1K−1 (at room temperature). We also report the GMR ratio of 17% and a large negative magnetothermal resistance effect (GMTR) of 33% in Cu/CoFe superlattice structure. The Boltzmann transport equation (BTE) is used to estimate the GMR ratio, and to investigate the effect of repeats, as well as the spin-dependent interface and boundary scatting on the transport properties of the GMR structure. Aside from the interesting underlying physics, these data can be used in the predictions of the Electrostatic Discharge (ESD) failure and self-heating in GMR heads.

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Formation and Electronic Structure of the Mn/GaAs(100) Interface

MRS Proceedings ◽

10.1557/proc-281-671 ◽

1992 ◽

Vol 281 ◽

Author(s):

X. Jin ◽

M. Zhang ◽

G. S. Dong ◽

Z. S. Li ◽

Xun Wang ◽

...

Keyword(s):

Electronic Structure ◽

Electron Density ◽

Density Of States ◽

Room Temperature ◽

Early Stage ◽

Ferromagnetic Phase ◽

Two Dimensional ◽

Interface Diffusion ◽

Electron Density Of States ◽

Fermi Edge

ABSTRACTFormation and electronic structure of the Mn/GaAs(100) interface grown at room temperature are studied by photoemission. The growth at early stage is identified to be in two-dimensional mode. The chemical reaction and the interface diffusion happened between Mn and GaAs are explored in some details. A ferromagnetic phase of Mn overlayer at early stage is deduced from the change of electron density of states near the Fermi edge.

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Giant Magnetoresistance in Single Layer and Multilayer Phase Separating Alloy Films

MRS Proceedings ◽

10.1557/proc-313-419 ◽

1993 ◽

Vol 313 ◽

Cited By ~ 1

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.

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Structural, Magnetic, and Electrical Properties of BiFe1-xMnxO3 Thin Films

MRS Proceedings ◽

10.1557/proc-1199-f03-26 ◽

2009 ◽

Vol 1199 ◽

Author(s):

Danilo G Barrionuevo ◽

Surinder P Singh ◽

Maharaj S. Tomar

Keyword(s):

Thin Films ◽

Room Temperature ◽

Magnetic Measurements ◽

Sol Gel ◽

Ion Concentration ◽

Ferromagnetic Phase ◽

X Ray Diffraction ◽

X Ray ◽

Si Substrates ◽

Sol Gel Process

AbstractWe synthesized BiFe1-xMnxO3 (BFMO) for various compositions by sol gel process and thin films were deposited by spin coating on platinum Pt/Ti/SiO2/Si substrates. X-ray diffraction shows all the diffraction planes corresponding to rhombohedrally distorted perovskite BiFeO3 structure. The absence of any impurity phase in the films suggests the incorporation Mn ion preferentially to Fe site in the structure for low concentration. Magnetic measurements reveal the formation of ferromagnetic phase at room temperature with increased Mn substitution. On the other hand, ferroelectric polarization decreases with increasing Mn ion concentration. Raman studies suggest the dopant induced structural distortion.

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Room temperature high Giant Magnetoresistance graphene based spin valve and its application for realization of logic gates

Physics Letters A ◽

10.1016/j.physleta.2019.126171 ◽

2020 ◽

Vol 384 (7) ◽

pp. 126171 ◽

Cited By ~ 1

Author(s):

Muzafar Gani ◽

Khurshed A. Shah ◽

Shabir A. Parah ◽

Prabhakar Misra

Keyword(s):

Giant Magnetoresistance ◽

Room Temperature ◽

Spin Valve ◽

Logic Gates

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Giant Magnetoresistance in Hybrid Magnetic Nanostructures Including Both Layers and Clusters

MRS Proceedings ◽

10.1557/proc-384-415 ◽

1995 ◽

Vol 384 ◽

Cited By ~ 1

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.

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