Ferromagnetic Resonance in a Uniaxial Anisotropic Ferrite: BaFe12O19

Silber, L.; Tsantes, E.; Angelo, P.

doi:10.1063/1.1709321

Cited by 27 publications

(5 citation statements)

References 5 publications

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“…This mode softening behaviour combined with the normal Zeeman effect is the physical reason for the observed turnover point in magnon frequency. This is described in more detail for the sample measured [16] and in general [73,74] in the literature. Magnetocrystalline anisotropy has also been demonstrated to produce a magnon-Kerr nonlinearity in YIG [75][76][77][78].…”

Section: Applications Of Ferrites In Frequency Metrologymentioning

confidence: 99%

Experimental implementations of cavity-magnon systems: from ultra strong coupling to applications in precision measurement

et al. 2019

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Several experimental implementations of cavity-magnon systems are presented. First an Yttrium Iron Garnet (YIG) block is placed inside a re-entrant cavity where the resulting hybrid mode is measured to be in the ultra strong coupling (USC) regime. When fully hybridised the ratio between the coupling rate and uncoupled mode frequencies is determined to be g/ω=0.46. Next a thin YIG cylinder is placed inside a loop gap cavity. The bright mode of this cavity couples to the YIG sample and is similarly measured to be in the USC regime with ratio of coupling rate to uncoupled mode frequencies as g/ω=0.34. A larger spin density medium such as lithium ferrite (LiFe) is expected to improve couplings by a factor of 1.46 in both systems as coupling strength is shown to be proportional to the square root of spin density and magnetic moment. Such strongly coupled systems are potentially useful for cavity QED, hybrid quantum systems and precision dark matter detection experiments. The YIG disc in the loop gap cavity, is, in particular, shown to be a strong candidate for dark matter detection. Finally, a LiFe sphere inside a two post re-entrant cavity is considered. In past work it was shown that the magnon mode in the sample has a turnover point in frequency (Goryachev et al 2018 Phys. Rev. B 97 155129). Additionally, it was predicted that if the system was engineered such that it fully hybridised at this turnover point the cavity-magnon polariton transition frequency would become insensitive to both first and second order magnetic bias field fluctuations, a result useful for precision frequency applications. This work implements such a system by engineering the cavity mode frequency to near this turnover point, with suppression in sensitivity to second order bias magnetic field fluctuations shown.

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Section: Applications Of Ferrites In Frequency Metrologymentioning

confidence: 99%

Experimental implementations of cavity-magnon systems: from ultra strong coupling to applications in precision measurement

et al. 2019

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“…In the work in ref. 76 an increase in the frequency of ferromagnetic resonance was predicted for the transition of barium hexaferrite from the single-domain to the polydomain state. The reason for this is based on the effect of a demagnetizing field ( H d = 4π ρM S , where ρ – a crystallographic density of hexaferrite) between magnetic domains within hexaferrite ceramics, which is comparable in magnitude to the anisotropy field ( H a ) of unsubstituted barium hexaferrite ( H d ≈ 4.2 kOe vs. H a ≈ 18 kOe).…”

Section: Resultsmentioning

confidence: 94%

High-coercivity hexaferrite ceramics featuring sub-terahertz ferromagnetic resonance

et al. 2022

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“…At smaller fields (Field Range 1), the sphere is broken into magnetic domains with magnetization vectors in them aligned along the easy axis (or multiple easy axes for cubic anisotropy). As shown theoretically by Smith and Beljers 56 , in this regime, the resonance decreases to a finite value at the critical field, and then increases following the single-domain theory from Silber et al 55 .…”

Section: Magnetisation Properties Of Lithium Ferrite and Comparison T...mentioning

confidence: 52%

“…2 (B) and Fig. 3 (B) can be explained as mode softening 55 . This is seen in their magnetic field dependence resulting in a magnon magnetic field insensitivity (dB/df = 0) at B s = 0.191 T as seen in as turnover points in the magnon resonance dependence on the external field.…”

Section: Magnetisation Properties Of Lithium Ferrite and Comparimentioning

confidence: 97%

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Cavity magnon polaritons with lithium ferrite and three-dimensional microwave resonators at millikelvin temperatures

et al. 2018

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Single crystal Lithium Ferrite (LiFe) spheres of sub-mm dimension are examined at mK temperatures, microwave frequencies and variable DC magnetic field, for use in hybrid quantum systems and condensed matter and fundamental physics experiments. Strong coupling regimes of the photon-magnon interaction (cavity magnon polariton quasi-particles) were observed with coupling strength of up to 250 MHz at 9.5 GHz (2.6%) with magnon linewidths of order 4 MHz (with potential improvement to sub-MHz values). We show that the photon-magnon coupling can be significantly improved and exceed that of the widely used Yttrium Iron Garnet crystal, due to the small unit cell of LiFe, allowing twice more spins per unit volume. Magnon mode softening was observed at low DC fields and combined with the normal Zeeman effect creates magnon spin wave modes that are insensitive to first order order magnetic field fluctuations. This effect is observed in the Kittel mode at 5.5 GHz (and another higher order mode at 6.5 GHz) with a DC magnetic field close to 0.19 Tesla. We show that if the cavity is tuned close to this frequency, the magnon polariton particles exhibit an enhanced range of strong coupling and insensitivity to magnetic field fluctuations with both first order and second order insensitivity to magnetic field as a function of frequency (double magic point clock transition), which could potentially be exploited in cavity QED experiments.

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Ferromagnetic Resonance in a Uniaxial Anisotropic Ferrite: BaFe12O19

Cited by 27 publications

References 5 publications

Experimental implementations of cavity-magnon systems: from ultra strong coupling to applications in precision measurement

Experimental implementations of cavity-magnon systems: from ultra strong coupling to applications in precision measurement

High-coercivity hexaferrite ceramics featuring sub-terahertz ferromagnetic resonance

Cavity magnon polaritons with lithium ferrite and three-dimensional microwave resonators at millikelvin temperatures

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