Insulating nanomagnets driven by spin torque

Abstract

Magnetic insulators, such as yttrium iron garnet (Y${}_3$Fe${}_5$O${}_{12}$), are ideal materials for ultra-low power spintronics applications due to their low energy dissipation and efficient spin current generation and transmission. Recently, it has been realized that spin dynamics can be driven very effectively in micrometer-sized Y${}_3$Fe${}_5$O${}_{12}$/Pt heterostructures by spin-Hall effects. We demonstrate here the excitation and detection of spin dynamics in Y${}_3$Fe${}_5$O${}_{12}$/Pt nanowires by spin-torque ferromagnetic resonance. The nanowires defined via electron-beam lithography are fabricated by conventional room temperature sputtering deposition on Gd${}_3$Ga${}_5$O${}_{12}$ substrates and lift-off. We observe field-like and anti-damping-like torques acting on the magnetization precession, which are due to simultaneous excitation by Oersted fields and spin-Hall torques. The Y${}_3$Fe${}_5$O${}_{12}$/Pt nanowires are thoroughly examined over a wide frequency and power range. We observe a large change in the resonance field at high microwave powers, which is attributed to a decreasing effective magnetization due to microwave absorption. These heating effects are much more pronounced in the investigated nanostructures than in comparable micron-sized samples. By comparing different nanowire widths, the importance of geometrical confinements for magnetization dynamics becomes evident: quantized spin-wave modes across the width of the wires are observed in the spectra. Our results are the first stepping stones toward the realization of integrated magnonic logic devices based on insulators, where nanomagnets play an essential role.

References in corpus (21)

• The design and verification of Mumax3
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• Spin Hall Magnetoresistance Induced by a Non-Equilibrium Proximity Effect
• Comparative Measurements of Inverse Spin Hall and Magnetoresistance in YIG|Pt and YIG|Ta
• Spin pumping by parametrically excited exchange magnons
• Generation of coherent spin-wave modes in Yttrium Iron Garnet microdiscs by spin-orbit torque
• Electronic control of the spin-wave damping in a magnetic insulator
• Thickness and power dependence of the spin-pumping effect in Y3Fe5O12/Pt heterostructures measured by the inverse spin Hall effect
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• Spin waves in micro-structured yttrium iron garnet nanometer-thick films
• Spin Pumping Driven by Bistable Exchange Spin Waves
• Epitaxial patterning of nanometer-thick Y3Fe5O12 films with low magnetic damping
• Induced magneto-transport properties at palladium/yttrium iron garnet interface
• Spin-transfer torque based damping control of parametrically excited spin waves in a magnetic insulator
• Current-induced spin torque resonance of magnetic insulators affected by field-like spin-orbit torques and out-of-plane magnetizations
• Spectral shape deformation in inverse spin Hall voltage in Y3Fe5O12|Pt bilayers at high microwave power levels

Cited by in corpus (12)

• Roadmap on Spin-Wave Computing
• Ultra Thin Films of Yttrium Iron Garnet with Very Low Damping: A Review
• Pure spin currents in magnetically ordered insulator/normal metal heterostructures
• High frequency dynamics modulated by collective magnetization reversal in artificial spin ice
• Simultaneous Optical and Electrical Spin-Torque Magnetometry with Stroboscopic Detection of Spin-Precession Phase
• Fresnel diffraction of spin waves
• Spin wave diffraction model for perpendicularly magnetized films
• Determining complex spin mixing conductance and spin diffusion length from spin pumping experiments in magnetic insulator/heavy metal bilayers
• Spin-circuit representation of spin-torque ferromagnetic resonance
• Observation of thermally activated coherent magnon-magnon coupling in a magnonic hybrid system
• Correlation between structural and magnetic properties of epitaxial YIG films by pulsed laser deposition
• Disambiguating electrical detection of magnetization dynamics in magnetic insulators