Inverse Spin Hall Effect in Electron Beam Evaporated Topological Insulator Bi2Se3 Thin Film
Braj B Singh et al.
physica status solidi (RRL)–Rapid Research Letters 13 (3), 2018, 1800492
Spintronics exploiting pure spin current in ferromagnetic (FM)/heavy metals (HM) is a subject of intense research. Topological insulators having spin momentum locked surface states exhibit high spin–orbit coupling and thus possess a huge potential to replace the HM like Pt, Ta, W, etc. In this context, the spin pumping phenomenon in Bi2Se3/CoFeB bilayers has been investigated. Bi2Se3 thin films are fabricated by electron beam evaporation method on Si (100) substrate. In order to confirm the topological nature of Bi2Se3, low temperature magnetotransport measurement on a 30 nm thick Bi2Se3 film which shows 10% magnetoresistance (MR) at 1.5 K has been performed. A linear increase in MR with applied magnetic field indicates the presence of spin momentum‐locked surface states. A voltage has been measured at room temperature to quantify the spin pumping which is generated via inverse spin Hall effect (ISHE). For the separation of spin rectification effects mainly produced by the FM CoFeB layer, in plane angular dependence of the dc voltage with respect to applied magnetic field has been measured. Our analysis reveals that spin pumping induced ISHE is the dominant contribution in the measured voltage.
Homepage of
Prof. Dr. Subhankar Bedanta
Professor in Physics
Chief-Coordinator of Centre for Interdisciplinary Sciences (CIS), NISER
Laboratory for Nanomagnetism and Magnetic Materials (LNMM)
National Institute of Science Education and Research
Equipments in our laboratory
Multipurpose thin film and nanoparticle deposition chamber
It is an UHV chamber consists of
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3 dc sputter sources
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2 rf sputter sources
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4-target e-beam sources
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2-target thermal sources
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Nanoparticle source (Nanogen)
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atom source
Cluster deposition chamber
It is an HV chamber consists of
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3 dc/rf sputter sources
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3 effusion cells sputter sources
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in situ LEED
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In situ ion source
Pulsed Laser Deposition Technique
Substrate heater temperature range: 800 °C, multitarget high vacuum chamber, KrF laser with wavelength 248 nm, adjustable target to substrate distance, Good for oxide materials, capable to maintain the stoichiometry, etc
"This equipment is supported via the Department of Atomic Energy project"
Atomic Force microscope
It is capable of AFM, MFM and in magnetic field upto 0.15 Tesla
This equipment is supported via DST-Nanomission project.
Kerr microscopy
All longitudinal, transverse and polar Kerr microscopy is possible, magnetic field up to ~1.3 Tesla (in-plane) and ~1 Tesla (out-of-plane), temperature range 10 < T < 900 K.
Stroboscopic attachment capable of making imaging at MHz frequency
The stroboscopic system is supported via DST-SERB project
Mask Aligner for photolithography
Microfabrication of dots and antidots with dimensions of a few micron.
"This equipment is supported via the Department of Atomic Energy project"
SpectromagPT cryogenic system
Closed cycle cryostat from Oxford, UK. Temperature 1.7 to 300 K. Split pair magnet capable of producing field up to 7 Tesla. Transport and magnetotransport measurements are presently incorporated with Keithley nanovoltmeter.
"This equipment is supported via the Department of Atomic Energy project"
Ferromagnetic resonance set-up
FMR set-up procured from NanoOsc. Frequency range 2 to 17 GHz and magnetic field 1.5 kOe. We have developed the spin-torque FMR set-up.
"This equipment is supported via the Department of Atomic Energy project"
Quantum Design U.S.A. make MPMS3 set-up
Equipped with superconducting magnet (-7 Tesla to +7 Tesla field range), operating temperature range: 1.8 to 400 K, Ultra-low field (ULF) option, moment resolution ≤ 10-8 emu, Magnetic moment/magnetization/DC and AC susceptibility of a sample can be measured as a function of temperature and/or magnetic field, Sample: bulk/thin film/powder.
"This equipment is supported via the Department of Atomic Energy project"
Dielectric spectroscopy set-up
Temperature range: (10-300) K. For measurements, we can perform impedance, complex capacitance, permittivity, and Tan delta, etc.
"This equipment is supported via the Department of Atomic Energy project"
Magnetic Annealing System
Vector Network Analyser based FMR
FMR set-up where frequency range is upto 26 GHz.
Probe Station
Upcoming Equipment Installations
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ST-FMR(2023)
Equipments in common laboratory of school of Physical sciences
Xray-Diffraction (XRD)
From RIGAKU (Smart Lab) 3kW machine, various options available such as small angle X-ray reflectivity (XRR), grazing incidence x-ray diffraction (GIXRD), reciprocal space mapping (RSM).
Magneto Optic Kerr Effect (MOKE) Setup
Focused ion beam (FIB)
Scanning Electron Microscopy (NON-CRYOGENIC)
Equipments in center for interdisciplinary sciences (CIS) @ NISER
Raman Spectroscopy
Transmission electron microscopy (TEM)
Sample preparation unit
Transmission electron microscopy (TEM)
JEOL JEM F200
Scanning electron microscopy (SEM) cryogenic
