Spin-Dependent Electronic Transport in Granular Ferromagnets

Milner, A.; Gerber, A.; Groisman, Bella; Karpovsky, Mark G.; Gladkikh, A.

doi:10.1103/physrevlett.76.475

Cited by 268 publications

(131 citation statements)

References 21 publications

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“…7,8 Spin-dependent scattering in magnetic heterogeneous systems has also been the object of intense research in the past years since the discovery of giant magnetoresistance effect ͑GMR͒ in magnetic multilayers, 9 granular alloys, 10,11 magnetic tunnel junctions, 12,13 and granular solids composed of nanometric ferromagnetic ͑FM͒ particles in an insulating matrix ͑granular FM metals͒. [14][15][16][17][18] In the dielectric regime, granular FM metals show giant tunneling magnetoresistance, caused by spin-dependent tunneling of the conduction electrons at the magnetic-insulator interfaces. Electrons with spin parallel to the particle magnetization have larger probability for tunneling than those electrons with antiparallel spin, leading to an overall lower resistance when all magnetic particle moments are aligned than in the case of randomly orientated moments.…”

Section: Introductionmentioning

confidence: 99%

Tunneling magnetoresistance inCo−ZrO2granular thin films

et al. 2006

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Granular films composed of well defined nanometric Co particles embedded in an insulating ZrO 2 matrix were prepared by pulsed laser depositon in a wide range of Co volume concentrations ͑0.15Ͻ x Ͻ 0.43͒. High-resolution transmission electron microscopy ͑TEM͒ showed very sharp interfaces between the crystalline particles and the amorphous matrix. Narrow particle size distributions were determined from TEM and by fitting the low-field magnetic susceptibility and isothermal magnetization in the paramagnetic regime to a distribution of Langevin functions. The magnetic particle size varies little for Co volume concentrations x Ͻ 0.32 and increases as the percolation limit is approached. The tunneling magnetoresistance ͑TMR͒ was successfully reproduced using the Inoue-Maekawa model. The maximum value of TMR was temperatureindependent within 50-300 K, and largely increased at low T, suggesting the occurrence of higher-order tunneling processes. Consequently, the tunneling conductance and TMR in clean granular metals are dominated by the Coulomb gap and the inherent particle size distribution.

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Section: Introductionmentioning

confidence: 99%

Tunneling magnetoresistance inCo−ZrO2granular thin films

et al. 2006

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“…Such large MR has been related to spin scattering effects. [44] It is known that aligned spins have lower scattering which results in low MR and random spins have high scattering to result in high MR.…”

Section: Magnetotransport Studymentioning

confidence: 99%

Magnetic, morphological and structural investigations of CoFe/Si interfacial structures

Kumar

Srivastava

2014

Journal of Experimental Nanoscience

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CoFe/Si interfacial structures have been realised by electron beam evaporation of CoFe magnetic alloy on p-and n-Si substrates. These realised interfacial structures have been characterised from X-ray diffraction (XRD), atomic force microscopy (AFM), magnetic force microscopy (MFM) and magnetisation (M-H) characteristics. XRD data have shown the presence of CoFe (bcc phase) and b-FeSi 2 phases for CoFe/p-Si interfacial structures, whereas CoFe/n-Si interfacial structures have shown the presence of CoFe (bcc and fcc) phases along with Fe 3 Si, e-FeSi and b-FeSi 2 silicide phases having nanodimension crystallites. The M-H characteristics have shown the superparamagnetic type behaviour for CoFe/p-Si structure, whereas CoFe/n-Si structure shows a feature of interfacial antiferromagnetic (AF) coupling. The observed magnetic behaviour has been understood due to the presence of various magnetic phases and their nanosized grains. The MFM data of domain size have also been correlated with the observed magnetic behaviour. CoFe/n-Si structures have shown a significant feature of giant magnetoresistance (GMR) as compared to CoFe/p-Si structures. It has been found that CoFe/p-Si structures show a distinctly different behaviour than CoFe/n-Si structures for their chemical structure, morphology and magnetic behaviour.

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“…In ferromagnetic metal (FM)-insulator granular films, networks of magnetic tunnel junctions are formed. Thus, the TMR effect due to spin-dependent tunneling between neighboring FM dots has been intensively studied [8][9][10][11][12][13][14][15]. It is easy to produce such small metallic particles at granular systems.…”

Section: Introductionmentioning

confidence: 99%

“…To further develop functional ferromagnetic SET devices (SEDs) such as a three-terminal ferromagnetic single-electron transistor, exploration of insulating materials used in granular films is thought to be helpful. However, the materials reported so far are mainly oxides [8][9][10][11][12]16]. Fluorides having high resistivity due to the wider band gap and smaller dielectric constants than MgO and Al 2 O 3 are other possible candidates [20], but reports on FM-fluoride granular films have been rare [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Structural and electromagnetic characterizations of Fe–SrF₂granular films

Hosoya¹,

Arita²,

Hamada³

et al. 2006

J. Phys. D: Appl. Phys.

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Abstract.We investigate composite Fe-SrF 2 films to explore new materials showing the granular type tunneling magnetoresistance (TMR) effect. The films are composed of Fe nano-particles embedded in a SrF 2 matrix. The electromagnetic properties of the ferromagnetic metal-insulator films are confirmed, including super-paramagnetism, tunnel conduction, and TMR. We obtain a TMR of 3% at RT and 5% at 77 K. The film resistivity is much higher than that of oxide-based granular film. We also fabricate the nanostructures of granular films and aim at the application of the single-electron transistor. As a result, we observed Coulomb blockade (CB) region and CB oscillation at low temperature.

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Spin-Dependent Electronic Transport in Granular Ferromagnets

Cited by 268 publications

References 21 publications

Tunneling magnetoresistance inCo−ZrO2granular thin films

Tunneling magnetoresistance inCo−ZrO2granular thin films

Magnetic, morphological and structural investigations of CoFe/Si interfacial structures

Structural and electromagnetic characterizations of Fe–SrF₂granular films

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Spin-Dependent Electronic Transport in Granular Ferromagnets

Cited by 268 publications

References 21 publications

Tunneling magnetoresistance inCo−ZrO2granular thin films

Tunneling magnetoresistance inCo−ZrO2granular thin films

Magnetic, morphological and structural investigations of CoFe/Si interfacial structures

Structural and electromagnetic characterizations of Fe–SrF2granular films

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Structural and electromagnetic characterizations of Fe–SrF₂granular films