<i>Q</i>‐Factor Measurements

Luiten, Andre N.

doi:10.1002/0471654507.eme332

Cited by 8 publications

(9 citation statements)

References 51 publications

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“…Experimentally, we demonstrate that spin pumping [14] enables electrical detection of the hybrid magnon-photon modes, showing distinct features not seen in any previous spin pumping experiments. Theoretically, we develop a model based on the combination of a microwave LCR [15] and Landau Lifshitz Gilbert (LLG) equations, which explains the characteristic features found in our experiment. In addition, we discover the non-resonant magnon-photon coupling via spin pumping measurements, indicating that the standard interpretation of FMR damping might require revisions.…”

Section: Pacs Numbersmentioning

confidence: 91%

“…In the same rotational frame, the cavity resonance can be modeled by an artificial LCR circuit with inductor L, capacitor C, and resistor R, which carries the microwave current j + (t) ≡ j x (ω 0 /ω r ) + ij y = je −iωt . The LCR equation [15] determines the cavity mode and its phase function. With magnon-photon coupling, two coupling parameters K c and K m are introduced in two sets of coupling terms.…”

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confidence: 99%

“…1 shows that the spectral function for the uncoupled cavity mode and FMR is given by S c (ω) = 1/(ω 2 −ω 2 c +i2βω c ω) and S m (ω) = 1/(ω−ω r + iαω), respectively. Using the microwave input-output formalism [15] and spin pumping theory [14,18] in the limit of small external loss and small precession angle, respectively, we obtain |S 21 | ≈ 2κ 2βωω c |Im(S c )| and V SP = V 0 αω|Im(S m )| e x · (e y × e H ) for calculating the transmission coefficient and spin pumping voltage. Here κ ≪ 1 is the external loss rate of the cavity and V 0 is the maximum spin pumping voltage that depends on the sample, cavity mode, and microwave power.…”

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confidence: 99%

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Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems

et al. 2015

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We use electrical detection, in combination with microwave transmission, to investigate both resonant and non-resonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anti-crossing, line width evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach pave the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling. PACS numbers:Coupling between electrodynamics and magnetization dynamics is a subject of cross-disciplinary and longstanding interest.The nuclear magnetic resonance (NMR) community has studied this effect for decades by measuring the radiation damping of NMR [1]. Engineers have routinely utilized this effect for designing microwave [2] and THz devices [3]. In condensed matter physics, such a coupling leads to the magnon polariton [4], which is an elementary excitation characterized by an intrinsic excitation gap between ferromagnetic resonance (FMR) and ferromagnetic antiresonance [5]. Extrinsically, classical coupling of magnetization dynamics with its electrodynamic surrounding causes Faraday induction of both NMR [6] and FMR [7]. From the perspective of quantum physics, resonant spin-photon coupling plays a central role in utilizing quantum information [8].In 2010, a theoretical work of Soykal and Flatté [9] sparked excitement in the community of spintronics for studying the strong field interaction of magnons and microwave photons. Pioneering experiments have been performed at cryogenic temperatures by Huebl et al. [10] and Tabuchi et al. [11] on the ferromagnetic insulator Yttrium iron garnet (YIG) placed on/in a microwave cavity, in which a large normal mode splitting was found in the transmission measurements, indicating large quantumcoherent magnon-photon coupling. In October 2014, an experimental breakthrough was made by Zhang et al.[12], who demonstrated Rabi-oscillations of the coupled magnon-photon system at room temperature. In the same month, an ultrahigh cooperativity of 10 5 between magnon and photon modes was reported [13]. These exciting works reveal just the tip of the iceberg of the new field of cavity spintronics. * Current affiliation: Department of Physics and Astronomy, University of Denver, Colorado, 80208, USA † Electronic address: hu@physics.umanitoba.ca; URL: http://www.physics.umanitoba.ca/∼hu So far, experiments in this emerging field were performed by measuring either the transmission (S 21 ) or reflection coefficient (S 11 ) of the microwave cavity loaded with a YIG sample. The coupling strength was obtained by fitting these S parameters to the microwave input-output formalism with an added self-energy term attributed to the magnon-photon coupling. This sta...

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Section: Pacs Numbersmentioning

confidence: 91%

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confidence: 99%

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confidence: 99%

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Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems

et al. 2015

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“…We find it reassuring that two different techniques for two very different Q values provide very similar δ (Q) values. We do not have a consistent explanation, why every technique 11,12 (including ours) converge to this limit of δ (Q) ≈ 10 −3 but it hints at a common technical limit. We recommend to use Eq.…”

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confidence: 68%

“…Time domain based methods were also developed 12 to study the microwave resonator parameters. The so-called decrement method observes the transient resonator response when a microwave excitation, whose frequency is in resonance with the resonator, is switched on or off 12,15,16 .…”

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confidence: 99%

A time domain based method for the accurate measurement of Q-factor and resonance frequency of microwave resonators

Gyüre

Márkus

Bernáth

et al. 2015

Review of Scientific Instruments

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We present a novel method to determine the resonant frequency and quality factor of microwave resonators which is faster, more stable, and conceptually simpler than the yet existing techniques. The microwave resonator is irradiated at a frequency away from its resonance. It then emits an exponentially decaying radiation at its eigen-frequency when the excitation is rapidly switched off. The emission is down-converted with a microwave mixer, digitized and its Fourier transformation (FT) directly yields the resonance curve in a single shot. Being an FT based method, this technique possesses the Fellgett (multiplex) and Connes (accuracy) advantages and it conceptually mimics that of pulsed nuclear magnetic resonance. We also establish a novel benchmark to compare accuracy of the different approaches of microwave resonator measurements. This shows that the present method have similar accuracy to the existing ones.

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Heating Causes Nonlinear Microwave Absorption Anomaly in Single‐Walled Carbon Nanotubes

Márkus

Gyüre-Garami

Sági

et al. 2018

Physica Status Solidi (b)

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Microwave impedance measurements indicate a nonlinear absorption anomaly in single‐walled carbon nanotubes at low temperatures (below 20 K). We investigate the nature of the anomaly using a time resolved microwave impedance measurement technique. It proves that the anomaly has an extremely slow, a few hundred second long dynamics. This strongly suggests that the anomaly is not caused by an intrinsic electronic effect and that it is rather due to a slow heat exchange between the sample and the environment.

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Q‐Factor Measurements

Cited by 8 publications

References 51 publications

Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems

Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems

A time domain based method for the accurate measurement of Q-factor and resonance frequency of microwave resonators

Heating Causes Nonlinear Microwave Absorption Anomaly in Single‐Walled Carbon Nanotubes

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