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Title: Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi 2Te 3 topological insulator thin films

Abstract

Anomalous Hall effect (AHE) was recently discovered in magnetic element-doped topological insulators (TIs), which promises low power consumption and high efficiency spintronics and electronics. This discovery broadens the family of Hall sensors. In this paper, AHE sensors based on Cr-doped Bi 2Te 3 topological insulator thin films are studied with two thicknesses (15 and 65 nm). It is found, in both cases, that ultrahigh Hall sensitivity can be obtained in Cr-doped Bi 2Te 3. Hall sensitivity reaches 1666 Ω/T in the sensor with the 15 nm TI thin film, which is higher than that of the conventional semiconductor HE sensor. The AHE of 65 nm sensors is even stronger, which causes the sensitivity increasing to 2620 Ω/T. Furthermore, after comparing Cr-doped Bi 2Te 3 with the previously studied Mn-doped Bi 2Te 3 TI Hall sensor, the sensitivity of the present AHE sensor shows about 60 times higher in 65 nm sensors. Furthermore, the implementation of AHE sensors based on a magnetic-doped TI thin film indicates that the TIs are good candidates for ultrasensitive AHE sensors.

Authors:
 [1];  [1];  [2];  [1]
  1. Iowa State Univ., Ames, IA (United States)
  2. Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1321967
Report Number(s):
IS-J-9028
Journal ID: ISSN 0018-9464
Grant/Contract Number:
AC02-07CH11358
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
IEEE Transactions on Magnetics
Additional Journal Information:
Journal Volume: 52; Journal Issue: 7; Journal ID: ISSN 0018-9464
Publisher:
Institute of Electrical and Electronics Engineers. Magnetics Group
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; sensitivity; Anomalous Hall effect sensor; topological insulators; thin films; temperature sensors; Hall effect; conductivity; charge carrier density; temperature measurement; magnetic hysteresis

Citation Formats

Ni, Y., Zhang, Z., Nlebedim, I. C., and Jiles, D. C.. Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi2Te3 topological insulator thin films. United States: N. p., 2016. Web. doi:10.1109/TMAG.2016.2519512.
Ni, Y., Zhang, Z., Nlebedim, I. C., & Jiles, D. C.. Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi2Te3 topological insulator thin films. United States. doi:10.1109/TMAG.2016.2519512.
Ni, Y., Zhang, Z., Nlebedim, I. C., and Jiles, D. C.. Fri . "Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi2Te3 topological insulator thin films". United States. doi:10.1109/TMAG.2016.2519512. https://www.osti.gov/servlets/purl/1321967.
@article{osti_1321967,
title = {Ultrahigh sensitivity of anomalous Hall effect sensor based on Cr-doped Bi2Te3 topological insulator thin films},
author = {Ni, Y. and Zhang, Z. and Nlebedim, I. C. and Jiles, D. C.},
abstractNote = {Anomalous Hall effect (AHE) was recently discovered in magnetic element-doped topological insulators (TIs), which promises low power consumption and high efficiency spintronics and electronics. This discovery broadens the family of Hall sensors. In this paper, AHE sensors based on Cr-doped Bi2Te3 topological insulator thin films are studied with two thicknesses (15 and 65 nm). It is found, in both cases, that ultrahigh Hall sensitivity can be obtained in Cr-doped Bi2Te3. Hall sensitivity reaches 1666 Ω/T in the sensor with the 15 nm TI thin film, which is higher than that of the conventional semiconductor HE sensor. The AHE of 65 nm sensors is even stronger, which causes the sensitivity increasing to 2620 Ω/T. Furthermore, after comparing Cr-doped Bi2Te3 with the previously studied Mn-doped Bi2Te3 TI Hall sensor, the sensitivity of the present AHE sensor shows about 60 times higher in 65 nm sensors. Furthermore, the implementation of AHE sensors based on a magnetic-doped TI thin film indicates that the TIs are good candidates for ultrasensitive AHE sensors.},
doi = {10.1109/TMAG.2016.2519512},
journal = {IEEE Transactions on Magnetics},
number = 7,
volume = 52,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 2016},
month = {Fri Jul 01 00:00:00 EDT 2016}
}

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Free Publicly Available Full Text
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Citation Metrics:
Cited by: 2works
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  • Hall-effect (HE) sensors based on high-quality Mn-doped Bi 2Te 3 topological insulator (TI) thin films have been systematically studied in this paper. Improvement of Hall sensitivity is found after doping the magnetic element Mn into Bi 2Te 3. The sensors with low Mn concentrations, Mn xBi 2-xTe 3, x = 0.01 and 0.08 show the linear behavior of Hall resistance with sensitivity about 5 Ω/T. And their Hall sensitivity shows weak dependence on temperature. For sensors with high Mn concentration (x = 0.23), the Hall resistance with respect to magnetic field shows a hysteretic behavior. Moreover, its sensitivity shows almostmore » eight times as high as that of the HE sensors with low Mn concentration. The highest sensitivity can reach 43 Ω/T at very low magnetic field. This increase of Hall sensitivity is caused by the occurrence of anomalous HE (AHE) after ferromagnetic phase transition. Our work indicates that the magnetic-element-doped TIs with AHE are good candidates for HE sensors.« less
  • Breaking time-reversal symmetry through magnetic doping of topological insulators has been identified as a key strategy for unlocking exotic physical states. Here, we report the growth of Bi{sub 2}Te{sub 3} thin films doped with the highest magnetic moment element Ho. Diffraction studies demonstrate high quality films for up to 21% Ho incorporation. Superconducting quantum interference device magnetometry reveals paramagnetism down to 2 K with an effective magnetic moment of ∼5 μ{sub B}/Ho. Angle-resolved photoemission spectroscopy shows that the topological surface state remains intact with Ho doping, consistent with the material's paramagnetic state. The large saturation moment achieved makes these films useful formore » incorporation into heterostructures, whereby magnetic order can be introduced via interfacial coupling.« less
  • We investigated the effect of magnetic doping on magnetic and transport properties of Bi{sub 2}Te{sub 3} thin films. Cr{sub x}Bi{sub 2−x}Te{sub 3} thin films with x = 0.03, 0.14, and 0.29 were grown epitaxially on mica substrate with low surface roughness (∼0.4 nm). It is found that Cr is an electron acceptor in Bi{sub 2}Te{sub 3} and increases the magnetization of Cr{sub x}Bi{sub 2−x}Te{sub 3}. When x = 0.14 and 0.29, ferromagnetism appears in Cr{sub x}Bi{sub 2−x}Te{sub 3} thin films, where anomalous Hall effect and weak localization of magnetoconductance were observed. The Curie temperature, coercivity, and remnant Hall resistance of thin films increase with increasingmore » Cr concentration. The Arrott-Noakes plot demonstrates that the critical mechanism of the ferromagnetism can be described better with 3D-Heisenberg model than with mean field model. Our work may benefit for the practical applications of magnetic topological insulators in spintronics and magnetoelectric devices.« less
  • Here, we report measurements of the polar Kerr effect, proportional to the out-of-plane component of the magnetization, in thin films of the magnetically doped topological insulator (Cr 0.12Bi 0.26Sb 0.62) 2Te 3. Measurements of the complex Kerr angle ΘK were performed as a function of photon energy in the range 0.8eV < ℏω < 3.0eV. We observed a peak in the real part of Θ K(ω) and zero crossing in the imaginary part that we attribute to a resonant interaction with a spin-orbit avoided crossing located ≈ 1.6 eV above the Fermi energy. The resonant enhancement allows measurement of themore » temperature and magnetic field dependence of Θ K in the ultrathin film limit, d ≥ 2 quintuple layers (QL). We find a sharp transition to zero remanent magnetization at 6 K for d < 8 QL, consistent with theories of the dependence of impurity spin interactions on film thickness and their location relative to topological insulator surfaces.« less
  • In this study, we deposited high quality (Sb 1–xBi x) 2Te 3 on mica substrate by molecular beam epitaxy and investigated their magnetotransport properties. It is found that the average surface roughness of thin films is lower than 2 nm. Moreover, a local maxima on the sheet resistance is obtained with x = 0.043, indicating a minimization of bulk conductivity at this composition. For (Sb 0.957Bi 0.043) 2Te 3, weak antilocalization with coefficient of -0.43 is observed, confirming the existence of 2D surface states. Moreover Shubnikov-de Hass oscillation behavior occurs under high magnetic field. The 2D carrier density is thenmore » determined as 0.81 × 10 16 m –2, which is lower than that of most TIs reported previously, indicating that (Sb 0.957Bi 0.043) 2Te 3 is close to ideal TI composition of which the Dirac point and Fermi surface cross within the bulk bandgap. Our results thus demonstrate the best estimated composition for ideal TI is close to (Sb 0.957Bi 0.043) 2Te 3 and will be helpful for designing TI-based devices.« less