Measurement of the intrinsic damping constant in individual nanodisks of YIG and YIG{\textbar}Pt

We report on an experimental study on the spin-waves relaxation rate in two series of nanodisks of diameter $\phi=$300, 500 and 700~nm, patterned out of two systems: a 20~nm thick yttrium iron garnet (YIG) film grown by pulsed laser deposition either bare or covered by 13~nm of Pt. Using a magnetic resonance force microscope, we measure precisely the ferromagnetic resonance linewidth of each individual YIG and YIG{\textbar}Pt nanodisks. We find that the linewidth in the nanostructure is sensibly smaller than the one measured in the extended film. Analysis of the frequency dependence of the spectral linewidth indicates that the improvement is principally due to the suppression of the inhomogeneous part of the broadening due to geometrical confinement, suggesting that only the homogeneous broadening contributes to the linewidth of the nanostructure. For the bare YIG nano-disks, the broadening is associated to a damping constant $\alpha = 4 \cdot 10^{-4}$. A 3 fold increase of the linewidth is observed for the series with Pt cap layer, attributed to the spin pumping effect. The measured enhancement allows to extract the spin mixing conductance found to be $G_{\uparrow \downarrow}= 1.55 \cdot 10^{14}~ \Omega^{-1}\text{m}^{-2}$ for our YIG(20nm){\textbar}Pt interface, thus opening large opportunities for the design of YIG based nanostructures with optimized magnetic losses.Comment: 4 pages, 3 figure

Inverse Spin Hall Effect in nanometer-thick YIG/Pt system

High quality nanometer-thick (20 nm, 7 nm and 4 nm) epitaxial YIG films have been grown on GGG substrates using pulsed laser deposition. The Gilbert damping coefficient for the 20 nm thick films is 2.3 x 10-4 which is the lowest value reported for sub-micrometric thick films. We demonstrate Inverse spin Hall effect (ISHE) detection of propagating spin waves using Pt. The amplitude and the lineshape of the ISHE voltage correlate well to the increase of the Gilbert damping when decreasing thickness of YIG. Spin Hall effect based loss-compensation experiments have been conducted but no change in the magnetization dynamics could be detected

Measurement of the intrinsic damping constant in individual nanodisks of Y3Fe5O12 and Y3Fe5O 12|Pt

We report on an experimental study on the spin-waves relaxation rate in two series of nanodisks of diameter / = 300, 500, and 700 nm, patterned out of two systems: a 20 nm thick yttrium iron garnet (YIG) film grown by pulsed laser deposition either bare or covered by 13nm of Pt. Using a magnetic resonance force microscope, we measure precisely the ferromagnetic resonance linewidth of each individual YIG and YIG Pt nanodisks. We find that the linewidth in the nanostructure is sensibly smaller than the one measured in the extended film. Analysis of the frequency dependence of the spectral linewidth indicates that the improvement is principally due to the suppression of the inhomogeneous part of the broadening due to geometrical confinement, suggesting that only the homogeneous broadening contributes to the linewidth of the nanostructure. For the bare YIG nano-disks, the broadening is associated to a damping constant α = 4 × 10-4. A threefold increase of the linewidth is observed for the series with Pt cap layer, attributed to the spin pumping effect. The measured enhancement allows to extract the spin mixing conductance found to be G = 1:55 × 1014 X-1 m-2 for our YIG(20nm) Pt interface, thus opening large opportunities for the design of YIG based nanostructures with optimized magnetic losses © 2014 AIP Publishing LLC

Full control of the spin-wave damping in a magnetic insulator using spin-orbit torque

© 2014 American Physical Society. It is demonstrated that the threshold current for damping compensation can be reached in a 5μm diameter YIG(20nm)|Pt(7nm) disk. The demonstration rests upon the measurement of the ferromagnetic resonance linewidth as a function of Idc using a magnetic resonance force microscope (MRFM). It is shown that the magnetic losses of spin-wave modes existing in the magnetic insulator can be reduced or enhanced by at least a factor of 5 depending on the polarity and intensity of an in-plane dc current Idc flowing through the adjacent normal metal with strong spin-orbit interaction. Complete compensation of the damping of the fundamental mode by spin-orbit torque is reached for a current density of ∼3×1011A·m-2, in agreement with theoretical predictions. At this critical threshold the MRFM detects a small change of static magnetization, a behavior consistent with the onset of an auto-oscillation regime

A low phase noise all cryogenic microwave oscillator based on a superconductor resonator

International audienceA 1 GHz full cryogenic oscillator is presented. The oscillator is based on a planar superconductor resonator featuring a loaded Q factor of 200 000 at low microwave input power (unloaded Q of 400 000) and on amplifying parts realized with SiGe bipolar transistors. The circuit is designed with an harmonic balance software and realized on alumina substrate. A nonlinear model is extracted at low temperature both for the transistor and the resonator. This double nonlinearity increases the difficulty of the oscillator design and implies a strategy to limit the power inside the resonator. The vibrations of the cryogenerator are also a serious issue to get high performance. Finally, the oscillator features a phase noise of-112 dBc/Hz at 100 Hz offset frequency and a phase noise floor of -170 dBc/Hz (100 kHz offset) at a temperature of 65 K

Measurement of the intrinsic damping constant in individual nanodisks of Y3Fe5O12 and Y3Fe5O 12|Pt

We report on an experimental study on the spin-waves relaxation rate in two series of nanodisks of diameter / = 300, 500, and 700 nm, patterned out of two systems: a 20 nm thick yttrium iron garnet (YIG) film grown by pulsed laser deposition either bare or covered by 13nm of Pt. Using a magnetic resonance force microscope, we measure precisely the ferromagnetic resonance linewidth of each individual YIG and YIG Pt nanodisks. We find that the linewidth in the nanostructure is sensibly smaller than the one measured in the extended film. Analysis of the frequency dependence of the spectral linewidth indicates that the improvement is principally due to the suppression of the inhomogeneous part of the broadening due to geometrical confinement, suggesting that only the homogeneous broadening contributes to the linewidth of the nanostructure. For the bare YIG nano-disks, the broadening is associated to a damping constant α = 4 × 10-4. A threefold increase of the linewidth is observed for the series with Pt cap layer, attributed to the spin pumping effect. The measured enhancement allows to extract the spin mixing conductance found to be G = 1:55 × 1014 X-1 m-2 for our YIG(20nm) Pt interface, thus opening large opportunities for the design of YIG based nanostructures with optimized magnetic losses © 2014 AIP Publishing LLC

Magnetic thin-film insulator with ultra-low spin wave damping for coherent nanomagnonics

Wave control in the solid state has opened new avenues in modern information technology. Surface-acoustic-wave-based devices are found as mass market products in 100 millions of cellular phones. Spin waves (magnons) would offer a boost in today's data handling and security implementations, i. e., image processing and speech recognition. However, nanomagnonic devices realized so far suffer from the relatively short damping length in the metallic ferromagnets amounting to a few 10 micrometers typically. Here we demonstrate that nm-thick YIG films overcome the damping chasm. Using a conventional coplanar waveguide we excite a large series of short-wavelength spin waves (SWs). From the data we estimate a macroscopic of damping length of about 600 micrometers. The intrinsic damping parameter suggests even a record value about 1 mm allowing for magnonics-based nanotechnology with ultra-low damping. In addition, SWs at large wave vector are found to exhibit the non-reciprocal properties relevant for new concepts in nanoscale SW-based logics. We expect our results to provide the basis for coherent data processing with SWs at GHz rates and in large arrays of cellular magnetic arrays, thereby boosting the envisioned image processing and speech recognition

Measurement of the intrinsic damping constant in individual nanodisks of Y3Fe5O12 and Y3Fe5O 12|Pt

We report on an experimental study on the spin-waves relaxation rate in two series of nanodisks of diameter / = 300, 500, and 700 nm, patterned out of two systems: a 20 nm thick yttrium iron garnet (YIG) film grown by pulsed laser deposition either bare or covered by 13nm of Pt. Using a magnetic resonance force microscope, we measure precisely the ferromagnetic resonance linewidth of each individual YIG and YIG Pt nanodisks. We find that the linewidth in the nanostructure is sensibly smaller than the one measured in the extended film. Analysis of the frequency dependence of the spectral linewidth indicates that the improvement is principally due to the suppression of the inhomogeneous part of the broadening due to geometrical confinement, suggesting that only the homogeneous broadening contributes to the linewidth of the nanostructure. For the bare YIG nano-disks, the broadening is associated to a damping constant α = 4 × 10-4. A threefold increase of the linewidth is observed for the series with Pt cap layer, attributed to the spin pumping effect. The measured enhancement allows to extract the spin mixing conductance found to be G = 1:55 × 1014 X-1 m-2 for our YIG(20nm) Pt interface, thus opening large opportunities for the design of YIG based nanostructures with optimized magnetic losses © 2014 AIP Publishing LLC

Measurement of the intrinsic damping constant in individual nanodisks of Y3Fe5O12 and Y3Fe5O 12|Pt

We report on an experimental study on the spin-waves relaxation rate in two series of nanodisks of diameter / = 300, 500, and 700 nm, patterned out of two systems: a 20 nm thick yttrium iron garnet (YIG) film grown by pulsed laser deposition either bare or covered by 13nm of Pt. Using a magnetic resonance force microscope, we measure precisely the ferromagnetic resonance linewidth of each individual YIG and YIG Pt nanodisks. We find that the linewidth in the nanostructure is sensibly smaller than the one measured in the extended film. Analysis of the frequency dependence of the spectral linewidth indicates that the improvement is principally due to the suppression of the inhomogeneous part of the broadening due to geometrical confinement, suggesting that only the homogeneous broadening contributes to the linewidth of the nanostructure. For the bare YIG nano-disks, the broadening is associated to a damping constant α = 4 × 10-4. A threefold increase of the linewidth is observed for the series with Pt cap layer, attributed to the spin pumping effect. The measured enhancement allows to extract the spin mixing conductance found to be G = 1:55 × 1014 X-1 m-2 for our YIG(20nm) Pt interface, thus opening large opportunities for the design of YIG based nanostructures with optimized magnetic losses © 2014 AIP Publishing LLC