A5000127771- Magnetic properties of thin films
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Magneto-Optical Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Magnetic Properties and Applications
- Molecular Junctions and Nanostructures
- Heusler alloys: electronic and magnetic properties
- Iron-based superconductors research
- Advancements in Semiconductor Devices and Circuit Design
- Magnetic Field Sensors Techniques
- ZnO doping and properties
- Mechanical and Optical Resonators
- Electronic and Structural Properties of Oxides
- Superconducting Materials and Applications
- Topological Materials and Phenomena
- Advanced Memory and Neural Computing
- Magnetic Properties of Alloys
- Metallic Glasses and Amorphous Alloys
- Gold and Silver Nanoparticles Synthesis and Applications
- Multiferroics and related materials
- Quantum Dots Synthesis And Properties
- Quantum Information and Cryptography
- Terahertz technology and applications
- Gyrotron and Vacuum Electronics Research
University of Cambridge
2016-2025
Lancaster University
2021
Sci-Tech Daresbury
2021
TU Dortmund University
2021
University of Leeds
2017-2021
Cavendish Hospital
2014
University of Rome Tor Vergata
2009
We demonstrate that an antiferromagnet can be employed for a highly efficient electrical manipulation of ferromagnet. In our study we use detection technique the ferromagnetic resonance driven by in-plane ac-current in NiFe/IrMn bilayer. At room temperature, observe antidamping-like spin torque acting on NiFe ferromagnet, generated current through IrMn antiferromagnet. A large enhancement torque, characterized effective spin-Hall angle exceeding most heavy transition metals, correlates with...
Understanding the transfer of spin angular momentum is essential in modern magnetism research. A model case generation magnons magnetic insulators by heating an adjacent metal film. Here, we reveal initial steps this Seebeck effect with <27fs time resolution using terahertz spectroscopy on bilayers ferrimagnetic yttrium-iron garnet and platinum. Upon exciting infrared laser pulse, a current $j_\textrm{s}$ arises same ~100fs scale which electrons thermalize. This observation highlights that...
In confined helimagnetic nanostructures, skyrmionic states in the form of incomplete and isolated skyrmion can emerge as ground state absence both external magnetic field magnetocrystalline anisotropy. this work, we study dynamic properties (resonance frequencies corresponding eigenmodes) thin film FeGe disk samples. We employ two different methods finite-element based micromagnetic simulation: eigenvalue ringdown method. The method allows us to identify all resonance eigenmodes that exist...
We investigate the influence of Meissner screening and trapped magnetic flux on magnetization dynamics for a Ni80Fe20 film sandwiched between two thick Nb layers (100 nm) using broadband (5-20 GHz) ferromagnetic resonance (FMR) spectroscopy. Below superconducting transition Tc Nb, significant zero-frequency line broadening (5-6 mT) DC field shift (50 to low are both observed if thickness is comparable London penetration depth films (>= 100 nm). attribute peculiar behaviors increased...
Using THz emission spectroscopy, we detect spin-photo-currents from a ferrimagnetic amorphous alloy GdFeCo to an adjacent Pt capping layer. The currents are generated upon excitation of GdFeCo/Pt heterostructure with femtosecond laser pulses. It is found that the polarization spin-polarized current determined by magnetic sublattice sensitivity rather than total magnetization, allowing for generation when net magnetization zero.
Recent experiments on strongly coupled microwave and ferromagnetic resonance modes have focused large volume bulk crystals such as yttrium iron garnet, typically of millimeter-scale dimensions. We extend these to lower volumes magnetic material by exploiting low-impedance lumped-element resonators. The low impedance equates a smaller mode volume, which allows us couple number spins in the ferromagnet. Compared previous experiments, we reduce participating two orders magnitude, while...
Interfaces between heavy metals (HMs) and antiferromagnetic insulators (AFIs) have recently become highly investigated debated systems in the effort to create spintronic devices able function at terahertz frequencies. Such heterostructures great technological potential because AFIs can generate sub-picosecond spin currents which HMs convert into charge signals. In this work we demonstrate an optically induced picosecond transfer interface Pt using time-resolved THz emission spectroscopy. We...
Recent progress in superconducting spintronics has highlighted the potential of superconductors (SCs) low-energy computing technologies. Most studies quasiparticle spin transport SCs have relied on dc measurements, but this one utilizes inverse spin-Hall effect induced by pumping to investigate spin-orbit coupling and Nb, standard material for applications. The authors not only provide reliable values angle spin-diffusion length also suggest a better device geometry electrical detection...
A recent ferromagnetic resonance study [Jeon et al., Nat. Mater. 17, 499 (2018)] has reported that spin pumping into a singlet superconductor (Nb) can be greatly enhanced over the normal state when Nb is coupled to large spin-orbit-coupling (SOC) sink such as Pt. This behavior been explained in terms of generation spin-polarized triplet supercurrents via SOC at Nb/Pt interface, acting conjunction with nonlocally induced magnetic exchange field. Here we report effect adding ferromagnet (Fe)...
Electrical detection of magnetization reversal typically requires three-terminal devices or nanoscopic heterostructures, such as magnetic tunnel junctions. Recently, the so-called unidirectional magnetoresistance has been discovered, which allows detecting reversals using two-terminal measurements. Here, authors theoretically and experimentally study in bulk ferromagnetic NiMnSb show that its origin is not directly related to current-induced spin accumulation gives rise spin-orbit torques....
We report an on-chip, electrically detected ferromagnetic resonance study on microbars made from GaAs/Fe(1 nm)/GaAs layers. Our experiments, performed at several different microwave frequencies and static magnetic field directions, enable us to observe a strong in-plane uniaxial anisotropy of the linewidth. attribute linewidth two magnon scattering process, supporting this by calculations possible broadening mechanisms. findings are useful for designing future high-performance spintronic...
We report Abrikosov vortex nucleation in Pt/Nb/Ni80Fe20/Nb/Pt proximity-coupled structures under oblique ferromagnetic resonance (FMR) that turns out to be detrimental superconducting spin pumping. By measuring an out-of-plane field-angle {\theta}H dependence and comparison with Pt-absent control samples, we show as increases, the degree of enhancement (suppression) pumping efficiency state for Pt-present (Pt-absent) sample diminishes it reverts normal value at = 90{\deg}. This can explained...
An antiferromagnet emits spin currents when time-reversal symmetry is broken. This typically achieved by applying an external magnetic field below and above the spin-flop transition or optical pumping. In this work we apply pump-THz emission spectroscopy to study picosecond pumping from metallic FeRh as a function of temperature. Intriguingly find that in low-temperature antiferromagnetic phase laser pulse induces large coherent pumping, while not crossing into ferromagnetic phase. With...
Abstract The optical manipulation of magnetism enabled by rare earth‐transition metal ferrimagnets holds the promise ultrafast, energy‐efficient spintronic technologies. This work investigates laser‐induced picosecond spin currents generated ferrimagnetic GdCo via terahertz emission spectroscopy. A suppression THz and current is observed at magnetization compensation when varying temperature or alloy composition in presence a magnetic field. It demonstrated that this due to formation domains...
Recent ferromagnetic resonance experiments and theory of Pt/Nb/Ni8Fe2 proximity-coupled structures strongly suggest that spin-orbit coupling (SOC) in Pt conjunction with a magnetic exchange field Ni8Fe2 are the essential ingredients to generate pure spin supercurrent channel Nb. Here, by substituting for perpendicularly magnetized Pt/Co/Pt spin-sink, we able demonstrate role SOC, show pumping efficiency across Nb is tunable controlling magnetization direction Co. By inserting Cu spacer weak...
We experimentally characterize the impedance of a single-electron transistor (SET) at an excitation frequency comparable to electron tunnel rate. In contrast usual radio-frequency-SET operations, signal is applied gate device. At zero source–drain bias, SET displays both resistive (Sisyphus resistance) and reactive (tunnelling capacitance) components its impedance. study bias dependence complex impedance, investigating response as rate becomes large with respect driving frequency. The...
Abstract Mn 3 Sn is a material that has attracted lot of attention lately for its topologically non-trivial band structure, which leads to very promising spintronic properties. In this work we experimentally demonstrate an epitaxially grown thin film acts as source THz radiation at room temperature when irradiated by femtosecond laser pulse. By combining various experimental measurements function pump polarisation, magnetic field, and sample orientation are able explain the origin emission...
We performed temperature-dependent optical pump–THz emission measurements in Y3Fe5O12 (YIG)|Pt from 5 K to room temperature the presence of an externally applied magnetic field. study dependence spin Seebeck effect and observe a continuous increase as is decreased, opposite what observed electrical measurements, where suppressed 0 approached. By quantitatively analyzing different contributions, we isolate spin-mixing conductance features that are correlated with bands magnon spectrum YIG.
This Roadmap provides an overview of the critical role materials in exploiting spin and topology for next-generation quantum technologies including computing, sensing, information storage networking devices. We explore key systems that support topological phenomena discuss their figures merit. Spin topology-based have several advantages over classical, charged-based counterparts, non-volatility, faster data processing speeds, higher integration densities lower power consumption. main...
5d metals are used in electronics because of their high spin–orbit coupling (SOC) leading to efficient spin-electric conversion. When C60 is grown on a metal, the electronic structure altered due hybridization and charge transfer. In this work, we measure spin Hall magnetoresistance for Pt/C60 Ta/C60, finding that they up factor 6 higher than those pristine metals, indicating 20–60% increase angle. At low fields 1–30 mT, presence increased anisotropic by 700%. Our measurements supported...
The level of the chemical potential is a fundamental parameter electronic structure physical system, which consequently plays an important role in defining properties active electrical devices. We directly measure shift relativistic band ferromagnetic semiconductor (Ga,Mn)As, controlled by changes its magnetic order parameter. Our device comprises non-magnetic aluminum single electron channel capacitively coupled to (Ga,Mn)As gate electrode. shifts are read out from Coulomb blockade...
In this work, we show that aluminium doped with low concentrations of magnetic impurities can be used to fabricate quantum devices intrinsic cooling capabilities. We single electron transistors made 2% Mn by using a standard multi angle evaporation technique and the quantity metal generates enough power achieve drop 160 mK in temperature at base our cryostat (300 mK). The mechanism is based on magneto-caloric effect from diluted moments.