相关论文: Auto-oscillation threshold and line narrowing in M…
We report the observation and micromagnetic analysis of current-driven magnetization switching in nanoscale ring-shaped magnetic tunnel junctions. When the electric current density exceeds a critical value of the order of $6\times…
Spin torque nano-oscillators realized by magnetization dynamics trapped in a current-induced potential are reported. We fabricated Ni$_{81}$Fe$_{19}$/Pt nanostructures and measured current-induced microwave emission from the structures. The…
We observe both dc voltage rectification and frequency conversion that occur when a reference microwave current is injected to a MgO based magnetic tunnel junction (MTJ). The rectification that is spin-transfer torque dependent is observed…
We measure the microwave signals produced by spin-torque-driven magnetization dynamics in patterned magnetic multilayer devices at room temperature, as a function of the angle of a magnetic field applied in the sample plane. We find strong…
Spin-torque oscillators are strong candidates as nano-scale microwave generators and detectors. However, because of large amplitude-phase coupling (non-linearity), phase noise is enhanced over other linear auto-oscillators. One way to…
The electronic structure and spin-dependent tunneling in epitaxial Fe/MgO/Fe(001) tunnel junctions are studied using first-principles calculations. For small MgO barrier thickness the minority-spin resonant bands at the two interfaces make…
Spin-torque nano-oscillators (STNOs) are promising nanoscale microwave sources for spintronic applications, serving as signal generators or elements in neuromorphic computing systems. In this paper, we investigate the experimental…
We created epitaxial magnetic tunnel junctions of FeCo/MgO/EuS on MgO buffered Si (100). Tunnel magnetoresistance reached up to 64% at 4.2 K. An unexpected fast drop of magnetoresistance was recorded for MgO thickness above 1 nm, which is…
We present experimental and numerical results from a real-time detection of time-correlated single-electron tunneling oscillations in a one-dimensional series array of small tunnel junctions. The electrons tunnel with a frequency f=I/e,…
It is shown that in a structure consisting of a superconducting ring-shaped electrode overlapped by a normal metal contact through a thin oxide barrier, measurements of the tunnel current in magnetic field can probe persistent currents in…
The critical current of the self-oscillation of spin torque oscillator (STO) consisting of a perpendicularly magnetized free layer and an in-plane magnetized pinned layer was studied by solving the Landau-Lifshitz-Gilbert (LLG) equation. We…
Coherent, self-sustained oscillation of magnetization in spin-torque oscillators (STOs) is a promising source for on-chip, nanoscale generation of microwave magnetic fields. Such fields could be used for local excitation of spin-wave…
Spin-diodes are usually resonant in nature (GHz frequency) and tuneable by magnetic field and bias current with performances, in terms of sensitivity and minimum detectable power, overcoming the semiconductor counterpart, i.e. Schottky…
A phase diagram of the magnetization dynamics is studied by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation in a spin torque oscillator consisting of asymmetric two free layers that are magnetized in in-plane direction. We…
A spin-torque nano-oscillator (STNO) driven by a ramped bias current can perform spectrum analysis quickly over a wide frequency bandwidth. The STNO spectrum analyzer operates by injection locking to external microwave signals and produces…
We report that low frequency (up to 200 kHz) noise spectra of magnetic tunnel junctions with areas ~10^{-10}cm^2$ at 10 Kelvin deviate significantly from the typical 1/f behavior found in large area junctions at room temperature. In most…
The influence of insertion of an ultra-thin NiO layer between the MgO barrier and ferromagnetic electrode in magnetic tunnel junctions has been investigated by measuring the tunneling magnetoresistance and the X-ray magnetic circular…
We demonstrate that magnetic oscillations of a current-biased magnetic nanocontact can be parametrically excited by a microwave field applied at twice the resonant frequency of the oscillation. The threshold microwave amplitude for the…
We study the theoretical conditions to excite a stable self-oscillation in a spin torque oscillator with an in-plane magnetized free layer and a perpendicularly magnetized pinned layer in the presence of magnetic field pointing in an…
We demonstrate the reduction of critical spin-transfer torque (STT) switching currents in Co-Fe-B/MgO based magnetic tunnel junctions (MTJ) with perpendicular magnetization anisotropy (PMA). The junctions yield tunnel magnetoresistance…