Effects of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers

Zhong, Guo; Mi, Wenbo; Aboljadayel, Razan; Zhang, Bei; Zhang, Qiang; Barba, Priscila; Manchon, Aurélien; Zhang, Xixiang

doi:10.1103/physrevb.86.104433

Cited by 73 publications

(42 citation statements)

References 32 publications

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“…The scaling exponent g 4 2 was usually observed in heterogeneous ferromagnetic systems, e.g., g = 3.7 in the Co-Ag granular films, 31 g = 2.6 in the Fe/Cr multilayers, 32 and g = 5.7 in the Co/Pd multilayers. 31,33 In Fig. 31,33 In Fig.…”

Section: View Article Onlinementioning

confidence: 99%

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe₄N films

Zhang

Wang

et al. 2015

Phys. Chem. Chem. Phys.

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The anomalous Hall effect (AHE) in the reactively sputtered epitaxial and polycrystalline γ'-Fe4N films is investigated systematically. The Hall resistivity is positive over the entire temperature range. The magnetization, carrier density and grain boundary scattering have a major impact on the AHE scaling law. The scaling exponent γ in the conventional scaling of ρAH ∝ ρ(γ)(xx) is larger than 2 in both the epitaxial and polycrystalline γ'-Fe4N films. Although γ > 2 has been found in heterogeneous systems due to the effects of the surface and interface scattering on AHE, γ > 2 is not expected in homogenous epitaxial systems. We demonstrated that γ > 2 results from residual resistivity (ρxx0) in γ'-Fe4N films. Furthermore, the side-jump and intrinsic mechanisms are dominant in both epitaxial and polycrystalline samples according to the proper scaling relation.

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Section: View Article Onlinementioning

confidence: 99%

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe₄N films

Zhang

Wang

et al. 2015

Phys. Chem. Chem. Phys.

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“…Other possible scenarios that can flip the sign of ρ A include the competition between bulk, surface, and interface contributions and the reversal of the Berry curvature as E F goes through the band‐crossing point due to spin–orbit interaction . The former scenario can account for the AHE in Co/Pd multilayers, where the T ‐dependent mean free path is comparable with the film thickness . The latter has been employed to explain the temperature/doping‐driven sign change in the ruthenates and ferromagnetic semiconductors .…”

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confidence: 99%

Magnetotransport Anomaly in Room‐Temperature Ferrimagnetic NiCo₂O₄ Thin Films

et al. 2018

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While previous studies of NCO have mainly centered on nanostructured and mesoporous materials, [6][7][8]15,16] it is of high research interest to examine the system in the epitaxial thin film form, especially for developing spintronic applications such as spinel-based magnetic tunnel junctions (MTJs). [17,18] To date, reports on high-quality NCO thin films have been scarce and mostly focused on the disorder-driven metal-insulator transition, [3,5,11,14,19,20] while the intrinsic magnetotransport properties in the metallic phase remain uncharted.In this work, we report the magnetotransport anomalies observed in 5-30 unit cell (uc) thick high-quality epitaxial NCO thin films. Below the magnetic ordering temperature, NCO exhibits strong out-of-plane magnetic anisotropy, linear magnetoresistance (MR), and robust anomalous Hall effect (AHE) that persist above room temperature. The longitudinal resistance exhibits a weak temperature dependence that cannot be directly correlated with the magnetic state of the system. The anomalous Hall conductivity (σ xy ) shows an unusual nonmonotonic temperature dependence, which changes sign in the thinner films. The relation between σ xy and the longitudinal conductivity (σ xx ) at the intermediate temperature range points to the dirty metal behavior in conjunction with the contribution from band intrinsic Berry phase effect, while the low-temperature characteristic can be attributed to disorderenhanced electron correlation. Our work provides critical information on how to manipulate the competing energy scales in this system to achieve tailored functionalities for spintronic applications.We deposited high-quality 5-30 uc epitaxial NCO films on (001)-oriented MgAl 2 O 4 (MAO) substrates. The bulk cubic lattice constant of NCO is 8.128 Å, subjecting to a 0.55% compressive strain when grown on MAO (a = 8.083 Å). X-ray diffraction (XRD) measurements show (001) growth with no impurity phases (Figure 1b). The calculated c-axis lattice constant is 8.196 Å, comparable with the reported values for strained films. [11,19] Figure 1c,d shows the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of a 17 uc NCO film, which reveal a homogeneous inverse spinel structure with high crystallinity. Atomic force microscopy (AFM) measurements show smooth surface morphology in these samples (Figure 1e), with typical root mean square roughness of 2-3 Å.The inverse spinel ferrimagnetic NiCo 2 O 4 presents a unique model system for studying the competing effects of crystalline fields, magnetic exchange, and various types of chemical and lattice disorder on the electronic and magnetic states. Here, magnetotransport anomalies in high-quality epitaxial NiCo 2 O 4 thin films resulting from the complex energy landscape are reported. A strong out-of-plane magnetic anisotropy, linear magnetoresistance, and robust anomalous Hall effect above 300 K are observed in 5-30 unit cell NiCo 2 O 4 films. The anomalous Hall resistance exhibits a nonmonotonic temperature dependence th...

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“…In these works, surface scattering in samples with different thicknesses was used to tune the magnetotransport properties. As reported in Co/Pd multilayers, surface scattering plays a different role on the AHE compared to interfacial scattering [8,19]. Therefore, it is necessary to examine the impact of spin-orbit-coupled interfacial scattering on the AHE using this scaling law, Eqs.…”

Section: Introductionmentioning

confidence: 99%

“…To this end, interfacial scattering in granular [5,6] and multilayer [7,8] systems and surface scattering [9][10][11] have been used to tune the longitudinal and anomalous Hall resistivity, experimentally. However, considering the side jump, the commonly used scaling law ρ AHE ∼ ρ γ xx is valid only for relatively homogeneous bulklike systems and invalid when the layer * Corresponding author: pengy@lzu.edu.cn † Corresponding author: xixiang.zhang@kaust.edu.sa thickness is of the order of or smaller than the mean free path (MFP) in multilayers [12].…”

Section: Introductionmentioning

confidence: 99%

Anomalous Hall effect in Fe/Au multilayers

Zhang

Wen

et al. 2016

Phys. Rev. B

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To understand the interfacial scattering effect on the anomalous Hall effect (AHE), we prepared multilayers of (Fe (36/n) nm /Au (12/n) nm ) n using an e-beam evaporator. This structure design allowed us to investigate the effect of interfacial scattering on the AHE, while keeping the samples' thickness and composition unchanged. We measured the (magneto)transport properties of the samples in a wide temperature range (10-310 K) with magnetic fields up to 50 kOe. We found that the scaling between the anomalous Hall resistivity (ρ AHE ) and longitudinal resistivity (ρ xx ) can be roughly described by ρ AHE ∼ ρ γ xx with γ = 2.65 ± 0.10 and 1.90 ± 0.04 for samples from n = 1 to n = 4 and samples from n = 4 to n = 12, respectively. Our quantitative analysis results showed that the interfacial scattering suppresses the contribution of the intrinsic mechanism and gives rise to a side-jump contribution.

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Effects of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers

Cited by 73 publications

References 32 publications

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe₄N films

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe₄N films

Magnetotransport Anomaly in Room‐Temperature Ferrimagnetic NiCo₂O₄ Thin Films

Anomalous Hall effect in Fe/Au multilayers

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Effects of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers

Cited by 73 publications

References 32 publications

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe4N films

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe4N films

Magnetotransport Anomaly in Room‐Temperature Ferrimagnetic NiCo2O4 Thin Films

Anomalous Hall effect in Fe/Au multilayers

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Scaling of anomalous Hall effects in facing-target reactively sputtered Fe₄N films

Scaling of anomalous Hall effects in facing-target reactively sputtered Fe₄N films

Magnetotransport Anomaly in Room‐Temperature Ferrimagnetic NiCo₂O₄ Thin Films