A5100714716- Magnetic properties of thin films
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Luminescence Properties of Advanced Materials
- Photorefractive and Nonlinear Optics
- Multiferroics and related materials
- Photonic and Optical Devices
- Advanced Memory and Neural Computing
- Magnetic and transport properties of perovskites and related materials
- Adhesion, Friction, and Surface Interactions
- Copper-based nanomaterials and applications
- Advanced Fiber Laser Technologies
- Metallic Glasses and Amorphous Alloys
- Quantum Dots Synthesis And Properties
- Radiation Detection and Scintillator Technologies
- Perovskite Materials and Applications
- Force Microscopy Techniques and Applications
- Ferroelectric and Negative Capacitance Devices
- Optical Coatings and Gratings
- Laser-Matter Interactions and Applications
- Physics of Superconductivity and Magnetism
- Characterization and Applications of Magnetic Nanoparticles
- Ferroelectric and Piezoelectric Materials
- Nonlinear Optical Materials Studies
- Microwave Dielectric Ceramics Synthesis
Beijing University of Chinese Medicine
2024
Shandong Jianzhu University
2021-2023
Institute of Microelectronics
2017-2021
Chinese Academy of Sciences
2005-2021
University of Chinese Academy of Sciences
2005-2018
University of Minnesota
2013-2015
Shandong University
2012
Tsinghua University
2008-2011
Institute of Physics
1994-2008
Shanghai Institute of Optics and Fine Mechanics
2005-2006
We describe a spin logic device with controllable magnetization switching of perpendicularly magnetized ferromagnet / heavy metal structures on ferroelectric (1-x)[Pb(Mg1/3Nb2/3)O3]-x[PbTiO3] (PMN-PT) substrate using current-induced spin-orbit torque. The devices were operated without an external magnetic field and controlled by voltages as low 10 V applied across the PMN-PT substrate, which is much lower compared to previous reports (500 V). deterministic smaller voltage was realized from...
Lithium niobate (LiNbO3, LN) channel and ridge waveguides have been successfully fabricated by He ion implantation, which has energy of 500 keV fluence 1.5×1016 ions/cm2 is combined with lithography the precise diamond dicing technique. The refractive index profile annealed LN planar waveguide was reconstructed. propagation loss a width 10 µm that widths 25 15 were investigated end-face coupling method. In our work, factors affect properties revealed.
In this work, we have combined shingled magnetic recording and bit patterned media (BPM) to achieve an areal density of 10 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${\rm Tb/in}^{2}$</tex></formula> . our design, the gradient write field along cross track direction is as high 700 Oe/nm. Composite BPM are utilized ratio thermal stability switching optimized accordingly. Assuming 5% distribution,...
In this work, the microstructure and magnetostriction effect of FeCo thin film are considered in micromagnetic simulations; therefore magnetic properties write pole can be calculated more accurately. Based on models, hysteresis loops films calculated. The simulation results show that has great coercive force films. Furthermore, initial permeability dynamic response studied. When easy axis is along cross-track direction, a 128 nm-wide 32 nm × nm-ABS tip real 8.0 at low frequencies roll-off...
We report on the fabrication and optimization of lithium niobate planar ridge waveguides at wavelength 633 nm. To obtain a waveguide, oxygen ions with an energy 3.0 MeV fluence 1.5×1015 ions/cm2 are implanted in polished face LiNbO3 crystals. For waveguides, loss 0.5 dB/cm is obtained after annealing 300°C for 30 min. The waveguide fabricated by diamond blade dicing method optimized waveguides. guiding properties investigated prism coupling end-face methods.
Feasibility of heat assisted magnetic recording for granular and bit-patterned media (BPM) is evaluated in the context various noises. Using micromagnetic simulation renormalized cells, we predict that jitter only 0.58 nm at a head speed 10 m/s bilayer structure FeRh/FePt when grain size 3.2 nm, validating possibility 6 Tb/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . We propose new FePt/Cr/X/FePt uses Cr layer to produce an...
In this letter, the negative-capacitance characteristics in a steady-state ferroelectric capacitor made of parallel domains are investigated by modeling. Through simulation and analysis dynamic process, we demonstrate that steady states can hold one domain at most. As result, manifested charge-voltage curve for multi-domain is remarkably different from S-shaped single-domain ferroelectric. The conclusion be readily generalized to capacitors. It indicates process polarization evolving time...
We present an alternative mechanism to control domain wall motion, whose directions are manipulated by the amplitude of electrical current rather than its sign when modulating exchange stiffness A while maintaining Dzyaloshinskii-Moriya interaction constant D. To confirm this mechanism, we observe type motion and demonstrate linear magnetic switching without hysteresis effect via adjusting a $\mathrm{Ta}/\mathrm{Pt}/\mathrm{Co}/\mathrm{Ta}$ multilayer device with ion implantations. further...
Micromagnetic simulations are widely utilized to simulate magnetic properties of materials, performance devices, and read/write processes in recording systems. In hard disk drives, the minimum size devices is now scaled down nanometer region; therefore, micromagnetics should be accurate enough include edge effects these ferromagnetic nano-devices. this work, we consider with flat structures. The analytical forms demagnetizing matrices for intra-cell inter-cell interactions calculated cubic...
The limits of discretization for reliable micromagnetic simulation are analyzed in square magnetic thin film devices. First the device is discretized by cubic cells, and an upper limit found ratio cell size to Neel exchange length. This increases with thinner larger size. reliability improved FDM-FFT method devices arbitrary shape verified two models different ways same device: domain structure dynamic switching properties similar Model A just cells B main body prism at edges.
We have studied through atomistic simulation the switching distribution of FePt grains subject to a declining temperature by evaluating probability at different time delays. It is found that smaller cooling rates and larger field angles, amplitudes, damping constants are favorable more deterministic switching, which can be interpreted as less magnetic recording jitter: difference during identified dominant factor. In particular, damping-induced lag between spin lattice has been shown...
An accurate micromagnetic model of the magnetic force microscope (MFM) tip has been developed to calculate effective dipole and its position in a simple point probe model, which are important quantitative explanation MFM images. The pyramid-shaped tips considered this paper; so cuboid cells body, as well triangular prism quadrangle pyramid at edge included accurately describe geometrical shape tip. field distribution analyzed, based on calculated domain structures with different materials...
We have investigated the feasibility of BPM for HAMR via Finite Difference Time Domain and atomistic simulation we substantiated 5 Tb/in2 with two filling factors 25% 56% even when maximum on-track bit temperature is below Curie temperature. The success this underheated switching attributed to sufficiently low anisotropy instead reduction gradient in cross-track direction almost doubled if optical head width reduced by half, indicating possibility higher areal densities. Moreover, contrary...
In this paper, we review our latest progress for heat-assisted magnetic recording (HAMR) systems. The temperature distribution has been computed using the finite difference time domain technique and by solving heat diffusion equation. Magnetic behavior calculated a renormalized cell (granular media) atomistic simulation [bit-patterned media (BPM)]. We find that ultimate density of HAMR on granular depends greatly grain size, with 5 nm pitch yielding ~4 Tb/in <sup...
The thermal distribution of granular media for heat assisted magnetic recording has been explored by the Fourier equation; particularly, effect conductivities in grain boundary extensively investigated. When conductivity is sufficiently small, provides a natural constraint to dissipation: effective in-plane can be ten times smaller than that FePt with decrease limited only dissipation through interlayer MgO. For low boundary, out plane gradient increases sharply owing inability spread....
We proposed a novel multilayer structure to realize the deterministic switching of perpendicularly magnetized layers by spin orbital torque from Hall effect through stray field engineering. In our design, pinned magnetic layer is introduced under heavy metal separated an insulator, generating in-plane in layer. have confirmed studying loops and dynamic processes micromagnetic simulation. The accounts for exhibited structure, ultimate reversal state predictable when applied current density...