Higher-order spin noise statistics

Li, Fuxiang; Saxena, Avadh; Smith, D. L.; Sinitsyn, Nikolai A.

doi:10.1088/1367-2630/15/11/113038

Cited by 26 publications

(40 citation statements)

References 50 publications

(81 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, only the full set of all correlators contains complete information about an interacting system. Higher-order correlations have been studied theoretically [51,52] and experimentally in magnetic systems such as spin glasses [5] and amorphous magnets [53], but we are not aware of any prior experimental studies of higherorder correlations of fluctuations in magnetic films in thermal equilibrium. Such correlators, however, play an important role in the theory of phase transitions and nonlinear thermodynamics [54].…”

Section: Higher-order Correlations Of the Magnetization Noisementioning

confidence: 99%

“…In general, magnetic systems can of course break time-reversal symmetry. However, Im[C 3 ] = 0 is expected to hold for Ising-Glauber spin dynamics that satisfy detailed balance at thermal equilibrium [51]. Figure 7 shows the real part of C 3 , measured at a location on the trilayer where m z (B z ) increases linearly (and the noise power S(ν) is large) when |B z | < B sat .…”

Section: Higher-order Correlations Of the Magnetization Noisementioning

confidence: 99%

See 1 more Smart Citation

Broadband Spectroscopy of Thermodynamic Magnetization Fluctuations through a Ferromagnetic Spin-Reorientation Transition

Balk¹,

Li²,

Gilbert³

et al. 2018

Phys. Rev. X

View full text Add to dashboard Cite

We use scanning optical magnetometry to study the broadband frequency spectra of spontaneous magnetization fluctuations, or “magnetization noise”, in an archetypal ferromagnetic film that can be smoothly tuned through a spin reorientation transition (SRT). The SRT is achieved by laterally varying the magnetic anisotropy across an ultrathin Pt/Co/Pt trilayer, from the perpendicular to in-plane direction, via graded Ar+ irradiation. In regions exhibiting perpendicular anisotropy, the power spectrum of the magnetization noise, S(ν), exhibits a remarkably robust ν−3/2 power law over frequencies ν from 1 kHz to 1 MHz. As the SRT region is traversed, however, S(ν) spectra develop a steadily-increasing critical frequency, ν0, below which the noise power is spectrally flat, indicating an evolving low-frequency cutoff for magnetization fluctuations. The magnetization noise depends strongly on applied in- and out-of-plane magnetic fields, revealing local anisotropies and also a field-induced emergence of fluctuations in otherwise stable ferromagnetic films. Finally, we demonstrate that higher-order correlators can be computed from the noise. These results highlight broadband spectroscopy of thermodynamic fluctuations as a powerful tool to characterize the interplay between thermal and magnetic energy scales, and as a means of characterizing phase transitions in ferromagnets.

show abstract

Section: Higher-order Correlations Of the Magnetization Noisementioning

confidence: 99%

Section: Higher-order Correlations Of the Magnetization Noisementioning

confidence: 99%

Broadband Spectroscopy of Thermodynamic Magnetization Fluctuations through a Ferromagnetic Spin-Reorientation Transition

Balk¹,

Li²,

Gilbert³

et al. 2018

Phys. Rev. X

View full text Add to dashboard Cite

show abstract

“…The relative strength Q r defined in Eq. (32) has been originally introduced in Ref. [15] to minimize this dependency.…”

Section: B Spin-noise Power Spectrum C2(ω)mentioning

confidence: 99%

“…Yet, quadrupolar interactions play an important role in the understanding of the long-time decay of higher-order spin response functions [29][30][31] especially at large magnetic fields above 1T. Since those fourth-order spin correlation functions [29][30][31] have been investigated in the time domain, it has been suggested [32,33] to extend the conventional SNS to higher-order spin noise correlations. The third-order spin correlation * These two authors contributed equally.…”

Section: Introductionmentioning

confidence: 99%

Fourth-order spin correlation function in the extended central spin model

2019

View full text Add to dashboard Cite

Spin noise spectroscopy has developed into a very powerful tool to access the electron spin dynamics. While the spin-noise power spectrum in an ensemble of quantum dots in a magnetic field is essentially understood, we argue that the investigation of the higher order cumulants promises to provide additional information not accessible by the conventional power noise spectrum. We present a quantum mechanical approach to the correlation function of the spin-noise power operators at two different frequencies for small spin bath sizes and compare the results with a simulation obtained from the classical spin dynamics for large number of nuclear spins. This bispectrum is defined as a two-dimensional frequency cut in the parameter space of the fourth-order spin correlation function. It reveals information on the influence of the nuclear-electric quadrupolar interactions on the longtime electron spin dynamics dominated by a magnetic field. For large bath sizes and spin lengths the quantum mechanical spectra converge to those of the classical simulations. The broadening of the bispectrum across the diagonal in the frequency space is a direct measure of the quadrupolar interaction strength. A narrowing is found with increasing magnetic field indicating a suppression of the influence of quadrupolar interactions in favor of the nuclear Zeeman effect.

show abstract

“…[11] In addition, Li et al developed theoretical methods to explore higher-order (third and fourth) cumulants of the spin noise in the frequency domain. [12,13] A lot of works have been done both theoretically and experimentally to understand the spin noise. Oestreich et al did SNS measurements under resonant as well as non-resonant probing conditions in an inhomogeneously broadened optical system (Rb vapor with 1 mbar of He buffer gas), and found that the SNS signal amplitude depends not only on the coherence between the ground and the excited states, but also on the ground-ground and excited-excited coherences in resonant and qusi-resonant probing conditions.…”

Section: Introductionmentioning

confidence: 99%

Spin noise spectroscopy of rubidium atomic gas under resonant and non-resonant conditions

Shi

Qian

et al. 2016

Chinese Phys. B

View full text Add to dashboard Cite

The spin fluctuation in rubidium atom gas is studied via all-optical spin noise spectroscopy (SNS). Experimental results show that the integrated SNS signal and its full width at half maximum (FWHM) strongly depend on the frequency detuning of the probe light under resonant and non-resonant conditions. The total integrated SNS signal can be well fitted with a single squared Faraday rotation spectrum and the FWHM dependence may be related to the absorption profile of the sample.

show abstract

Higher-order spin noise statistics

Cited by 26 publications

References 50 publications

Broadband Spectroscopy of Thermodynamic Magnetization Fluctuations through a Ferromagnetic Spin-Reorientation Transition

Broadband Spectroscopy of Thermodynamic Magnetization Fluctuations through a Ferromagnetic Spin-Reorientation Transition

Fourth-order spin correlation function in the extended central spin model

Spin noise spectroscopy of rubidium atomic gas under resonant and non-resonant conditions

Contact Info

Product

Resources

About