The planar Hall effect in thin foils of Ni-Fe alloy

Yau, K. L.; Chang, Jen-Chun

doi:10.1088/0305-4608/1/1/307

Cited by 14 publications

(11 citation statements)

References 6 publications

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“…Another support comes from the similarity with the planar Hall effect 35 . The planar Hall effect generates a voltage U P HE perpendicular to the current in ferromagnetic samples (width W) when the magnetization M 0 lies in the current-voltage plane.…”

Section: Asymmetric Lorentz Line Shapementioning

confidence: 90%

Microwave photovoltage and photoresistance effects in ferromagnetic microstrips

2007

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We investigate the dc electric response induced by ferromagnetic resonance in ferromagnetic Permalloy (Ni80Fe20) microstrips. The resulting magnetization precession alters the angle of the magnetization with respect to both dc and rf current. Consequently the time averaged anisotropic magnetoresistance (AMR) changes (photoresistance). At the same time the time-dependent AMR oscillation rectifies a part of the rf current and induces a dc voltage (photovoltage). A phenomenological approach to magnetoresistance is used to describe the distinct characteristics of the photoresistance and photovoltage with a consistent formalism, which is found in excellent agreement with experiments performed on in-plane magnetized ferromagnetic microstrips. Application of the microwave photovoltage effect for rf magnetic field sensing is discussed.

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Section: Asymmetric Lorentz Line Shapementioning

confidence: 90%

Microwave photovoltage and photoresistance effects in ferromagnetic microstrips

2007

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“…In this region, large changes in the magnitude of the anomalous Hall current as well as relative orientation of the Hall current with respect to the magnetization can be easily achieved by simple reorientation of the sample's magnetization. While the former could be used in order to, e.g., tune the relative magnitudes of the extrinsic and intrinsic anomalous Hall signal, 6,29 among the most straightforward applications of the latter could be a realization of the planar Hall effect (PHE), 38 which is related to the Hall effect in ferromagnetic materials observed in a two-dimensional geometry with electric field, with magnetization and the Hall current sharing the same sample plane. So far, it is believed that, in most of the cases, the PHE originates from anisotropic magnetoresistance in metallic ferromagnets, although the PHE mechanism stemming from the anomalous Hall effect due to noncollinearity of the magnetization in semiconductor-based materials has been also suggested.…”

Section: Anisotropic Ahc In 3dpt Alloysmentioning

confidence: 99%

Anisotropic intrinsic anomalous Hall effect in ordered3dPt alloys

2011

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By performing first-principles calculations, we investigate the intrinsic anomalous Hall conductivity (AHC) and its anisotropy in ordered L1 0 FePt, CoPt, and NiPt ferromagnets and their intermediate alloys. We demonstrate that the AHC in this family of compounds depends strongly on the direction of the magnetization M in the crystal. We predict that such pronounced orientational dependence in combination with the general decreasing trend of the AHC when going from FePt to NiPt leads to a sign change of the AHC upon rotating the magnetization direction in the crystal of CoPt alloy. We also suggest that, for a range of concentration x in Co x Ni 1−x Pt and Fe x Co 1−x Pt alloys, it is possible to achieve a complete quenching of the anomalous Hall current for a certain direction of the magnetization in the crystal. By analyzing the spin-resolved AHC in 3dPt alloys, we endeavor to relate the overall trend of the AHC in these compounds to the changes in their densities of d states around the Fermi energy upon varying the atomic number. Moreover, we show the generality of the phenomenon of anisotropic anomalous Hall effect by demonstrating its occurrence within the three-band tight-binding model.

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“…For PHE the magnetization M lies in the plane spanned by the current density j ¼ je x and the direction e y of the transverse voltage measurement, and for AHE the component of M perpendicular to j and e y matters. Although AMR has been known since Thomson's-later known as Lord Kelvin-observations in 1856 [6], PHE was discovered only a century later in polycrystalline permalloy [7]. More recently, PHE has also been found in crystalline La 2=3 Fe 1=3 MnO 3 [8] and as a very large effect at low temperatures in the dilute magnetic semiconductor (Ga,Mn)As [9].…”

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confidence: 99%

Origin of the Planar Hall Effect in NanocrystallineCo60Fe20B20

et al. 2011

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An angle dependent analysis of the planar Hall effect (PHE) in nanocrystalline single-domain Co 60 Fe 20 B 20 thin films is reported. In a combined experimental and theoretical study we show that the transverse resistivity of the PHE is entirely driven by anisotropic magnetoresistance (AMR). Our results for Co 60 Fe 20 B 20 obtained from first principles theory in conjunction with a Boltzmann transport model take into account the nanocrystallinity and the presence of 20 at. % boron. The ab initio AMR ratio of 0.12% agrees well with the experimental value of 0.22%. Furthermore, we experimentally demonstrate that the anomalous Hall effect contributes negligibly in the present case. DOI: 10.1103/PhysRevLett.107.086603 PACS numbers: 72.25.Ba, 71.70.Ej, 72.15.Gd Electron transport effects employing the electronic spin degree of freedom lie at the heart of spintronics and its applications not only in information technology [1] but more increasingly also in sensorics for biomedical purposes, where the utmost sensitivity for detecting minute magnetic stray fields is needed. The planar Hall effect (PHE) and the anomalous Hall effect (AHE) as well as tunneling magnetoresistance are promising phenomena for realizing highly sensitive sensors. From a materials point of view, nanocrystalline Co 60 Fe 20 B 20 (CoFeB) attracts growing attention since it combines large saturation magnetization with low coercivity [2,3], both favoring high sensitivities.PHE and AHE are both observed as a voltage transverse to the applied current [4,5] in contrast to the anisotropic magnetoresistance (AMR), which is measured in the longitudinal geometry. For PHE the magnetization M lies in the plane spanned by the current density j ¼ je x and the direction e y of the transverse voltage measurement, and for AHE the component of M perpendicular to j and e y matters. Although AMR has been known since Thomson's-later known as Lord Kelvin-observations in 1856 [6], PHE was discovered only a century later in polycrystalline permalloy [7]. More recently, PHE has also been found in crystalline La 2=3 Fe 1=3 MnO 3 [8] and as a very large effect at low temperatures in the dilute magnetic semiconductor (Ga,Mn)As [9]. The transverse resistance xy characterizing the PHE and the longitudinal resistivity xx denoting the AMR are given by [10] xy ¼ ð k À ? Þ sinÈ cosÈwhere k ( ? ) is the resistivity along (perpendicular to) the direction of the in-plane component of M, and È is the angle enclosed by j and M. A transverse voltage arises whenever the current is neither perpendicular nor parallel to the magnetization. Even though the AMR is a subtle spin-orbit effect, quantitatively reliable predictions from first principles based on the density functional theory (DFT) can be made [11,12]. In this Letter, we elucidate the role of AMR in the PHE in nanocrystalline Co 60 Fe 20 B 20 thin films experimentally and by ab initio calculations. We measure AMR and PHE in longitudinal and transverse four-probe transport experiments. The single-domain behavior enforced by an ...

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The planar Hall effect in thin foils of Ni-Fe alloy

Cited by 14 publications

References 6 publications

Microwave photovoltage and photoresistance effects in ferromagnetic microstrips

Microwave photovoltage and photoresistance effects in ferromagnetic microstrips

Anisotropic intrinsic anomalous Hall effect in ordered3dPt alloys

Origin of the Planar Hall Effect in NanocrystallineCo60Fe20B20

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