The Origin of the Giant Hall Effect in Metal-Insulator Composites

Sonntag, Joachim

doi:10.4236/ojcm.2016.63008

Cited by 4 publications

(2 citation statements)

References 44 publications

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“…Large ρ yx at room temperature has also been obtained in ferromagnetic semiconductors 28 and metal-insulator composites 29 . According to the established classification of AHE origins 11,30,31 , those highly resistive materials, however, are in the poorly conductive region ( σ xx < ~3 × 10 3 Ω −1 cm −1 ).…”

Section: Discussionmentioning

confidence: 92%

Fe-Sn nanocrystalline films for flexible magnetic sensors with high thermal stability

Satake

Fujiwara

Shiogai

et al. 2019

Sci Rep

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The interplay of magnetism and spin-orbit coupling on an Fe kagome lattice in Fe 3 Sn 2 crystal produces a unique band structure leading to an order of magnitude larger anomalous Hall effect than in conventional ferromagnetic metals. In this work, we demonstrate that Fe-Sn nanocrystalline films also exhibit a large anomalous Hall effect, being applicable to magnetic sensors that satisfy both high sensitivity and thermal stability. In the films prepared by a co-sputtering technique at room temperature, the partial development of crystalline lattice order appears as nanocrystals of the Fe-Sn kagome layer. The tangent of Hall angle, the ratio of Hall resistivity to longitudinal resistivity, is maximized in the optimal alloy composition of close to Fe 3 Sn 2 , implying the possible contribution of the kagome origin even though the films are composed of nanocrystal and amorphous-like domains. These ferromagnetic Fe-Sn films possess great advantages as a Hall sensor over semiconductors in thermal stability owing to the weak temperature dependence of the anomalous Hall responses. Moreover, the room-temperature fabrication enables us to develop a mechanically flexible Hall sensor on an organic substrate. These demonstrations manifest the potential of ferromagnetic kagome metals as untapped reservoir for designing new functional devices.

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Section: Discussionmentioning

confidence: 92%

Fe-Sn nanocrystalline films for flexible magnetic sensors with high thermal stability

Satake

Fujiwara

Shiogai

et al. 2019

Sci Rep

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“…(3) (Sonntag, 2016a). R, R A and R B are the Hall coefficients of the composite and the phases A and B, respectively.…”

Section: The Physical Backgroundmentioning

confidence: 99%

Electron Theory of Metals - Answers to Unsolved Problems/Questions

Sonntag

2023

JMSR

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Why are there simple metals with positive thermopower? Why are there metals with a negative temperature coefficient of resistivity? What is the reason for the Mooij correlation and the Giant Hall effect? These are questions that have not yet been answered with the known transport theories (Mizutani, 2001, pp. 474). However, they can be answered by considering the phenomenon of phase separation connected with an electron transfer between the phases. In this paper answers are proposed to these questions mentioned. Answers to other fundamental problems/questions are proposed in the recently published book (Sonntag, 2023).

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Size-dependent electrical transport properties in Co nanocluster-assembled granular films

Zhang

Wang

et al. 2017

Sci Rep

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A series of Co nanocluster-assembled films with cluster sizes ranging from 4.5 nm to 14.7 nm were prepared by the plasma-gas-condensation method. The size-dependent electrical transport properties were systematically investigated. Both of the longitudinal resistivity () and saturated anomalous Hall resistivity () continuously increased with the decrease of the cluster sizes (d). The firstly increased and then decreased with increasing the temperature for all samples, which could be well described by involving the thermally fluctuation-induced tunneling (FIT) process and scattering. The tunneling effect was verified to result in the invalidation of classical anomalous Hall effect (AHE) scaling relation. After deducting the contribution from tunneling effect to , the AHE scaling relation between and the scattering resistivity () by varying the temperature was reconstructed. The value of scaling exponent γ increased with increasing Co cluster sizes. The size dependence of γ might be qualitatively interpreted by the interface and surface-induced spin flip scattering. We also determined the scaling relation between and at 5 K by changing the Co cluster sizes, and a large value of γ = 3.6 was obtained which might be ascribed to the surface and interfacial scattering.

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The Origin of the Giant Hall Effect in Metal-Insulator Composites

Cited by 4 publications

References 44 publications

Fe-Sn nanocrystalline films for flexible magnetic sensors with high thermal stability

Fe-Sn nanocrystalline films for flexible magnetic sensors with high thermal stability

Electron Theory of Metals - Answers to Unsolved Problems/Questions

Size-dependent electrical transport properties in Co nanocluster-assembled granular films

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