Low-Temperature Acoustic Relaxation in Ni—Fe Ferrites

Fine, M. E.; Kenney, Nancy T.

doi:10.1103/physrev.96.1487

Cited by 21 publications

(4 citation statements)

References 5 publications

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“…Fine and Kenney 27 have measured sound absorption in single crystals of similar ferrites and found a loss peak which they identified with the same valence-electron rearrangement as that excited by stress. They deduced an activation energy of 0-026-0-055 eV, which is in reasonable agreement with the values found above.…”

Section: F) (31)mentioning

confidence: 93%

Losses in ferrites: single-crystal studies

Galt¹

1957

Proceedings of the IEE - Part B: Radio and Electronic Engineering

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A simple experiment on ferromagnetic resonance absorption in single crystals of ferrites is described, and the method of deducing physically significant parameters of the ferrite from the results of such experiments is derived. Results at 24000Mc/s, and the parameters deduced from them in this way, are given for (NiO)o-75(FeO)o-25Fe203 and for (NiO) 0 .95(FeO)o-05Fe 2 0 3 . The results indicate that the presence of divalent iron gives rise to an important loss mechanism. Another experiment is described in which the motion of an individual ferromagnetic domain boundary is observed in a single crystal, and results of such an experiment on (NiO)o-75(FeO)o-2sFe203 at various temperatures are given. They indicate that the damping of domainwall motion in this material increases by a large factor (100 or more) as the temperature decreases from 300 to 77° K. An elementary thermodynamical calculation is given which describes both types of experimental results in terms of a torque relaxation. Elastic-constant and conductivity measurements which yield relevant results are also discussed briefly. LIST OF PRINCIPAL SYMBOLS/ = Angular momentum of ferromagnetic electrons per unit volume. M = Magnetic moment per unit volume. H = Magnetic field. y = Gyromagnetic ratio (y = MIX). A = Damping parameter. iV*, N£ = Demagnetizing factors used in representing effective field of magnetocrystalline anisotropy on M. W a = Magnetocrystalline anisotropy energy. K\ = Magnetocrystalline anisotropy energy constant. «i» «2» a 3 -Direction cosines of magnetization with respect to cubic axes. fi(0) = Angular dependence of the effect of magnetocrystalline anisotropy on ferromagnetic resonance field in (110) plane of a cubic crystal. z = Displacement of ferromagnetic domain wall, i, z = First and second time derivatives of z. m w = Mass of ferromagnetic domain wall. j8 = Viscous damping constant of ferromagnetic domain wall. a = Stiffness of ferromagnetic domain wall. M s = Saturation magnetization of a magnetic material.

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Section: F) (31)mentioning

confidence: 93%

Losses in ferrites: single-crystal studies

Galt¹

1957

Proceedings of the IEE - Part B: Radio and Electronic Engineering

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“…The landmark is probably the seminal paper of Kittel [75], who explained the benefits of coupling acoustic-waves (AW) with spin-waves (SW) in order to confer to the former waveform a tunable and non-reciprocal character. Since then, the subject has accumulated a vast amount of literature that spans a wide range of ferromagnetic materials from metals [108], to magnetic semiconductors [109,110], and electrical insulators [111,112,113]. From the start, ferrite garnets [114] have been the subject of an intense focus because of their ultra-low internal frictions.…”

Section: Magneto-elastic Couplingmentioning

confidence: 99%

Spin Insulatronics

Brataas,

van Wees,

Klein

et al. 2020

Preprint

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Spin insulatronics covers efforts to generate, detect, control, and utilize high-fidelity pure spin currents and excitations inside magnetic insulators. Ultimately, the new findings may open doors for pure spin-based information and communication technologies. The aim is to replace moving charges with dynamical entities that utilize low-dissipation coherent and incoherent spin excitations in antiferromagnetic and ferromagnetic insulators. The ambition is that the new pure spin-based system will suffer reduced energy losses and operate at high frequencies. In magnetic insulators, there are no mobile charge carriers that can dissipate energy. Integration with conventional electronics is possible via interface exchange interactions and spinorbit couplings. In this way, the free electrons in the metals couple to the localized spins in the magnetic insulators. In turn, these links facilitate spin-transfer torques and spin-orbit torques across metal-insulator interfaces and the associated phenomena of spin-pumping and charge-pumping. The interface couplings also connect the electron motion inside the metals with the spin fluctuations inside the magnetic insulators. These features imply that the system can enable unprecedented control of correlations resulting from the electron-magnon interactions. We review recent developments to realize electric and thermal generation, manipulation, detection, and control of pure spin information in insulators.

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“…Fine and Kenney [12][13] have studied the internal friction in the single crystals of magnetite and Ni-Fe ferrite. Gibbons [14] studied the variation in internal friction with temperature for single crystals of manganese ferrite, magnetite, manganese zinc ferrite and nickel iron ferrites at low temperature using resonant piezoelectric method in the frequency range 100-150 kHz.…”

Section: Resume Of Important Investigations On the Internal Friction ...mentioning

confidence: 99%

Studies on Internal Friction and Curie Temperature of NiMgCuZn Spinel Ferrites for Micro-Inductor Applications

Varalaxmi

Sivakumar

Virk

2015

SSP

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Three series of NiMgCuZn ferrites were prepared by conventional double sintering ceramic process. The formation of single phase in these ferrites was confirmed by X-ray diffraction. A brief review of the important investigations carried out on the internal friction behaviour of NiMgCuZnFe2O4, in the temperature range 40oC to 360oC, has been reported. In the present investigation, the composite piezoelectric resonator method has been used. The effect of compositional changes of ferrites on Curie temperature and internal friction are reported. Results and discussions on the temperature variation of internal friction of the three series of NiMgCuZnFe2O4samples are discussed. In all the series studied, only single stress induced relaxation peaks are observed. These studies were carried out to develop a ferrite composition for their use as core materials for microinductor applications. The results are explained in the light of structural phase transitions.

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Low-Temperature Acoustic Relaxation in Ni—Fe Ferrites

Cited by 21 publications

References 5 publications

Losses in ferrites: single-crystal studies

Losses in ferrites: single-crystal studies

Spin Insulatronics

Studies on Internal Friction and Curie Temperature of NiMgCuZn Spinel Ferrites for Micro-Inductor Applications

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