Phonon renormalization and damping in a Heisenberg ferromagnet

Wesselinowa, J. M.

doi:10.1007/bf01307285

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…To interpret this behaviour, several mechanisms have been proposed. Wesselinowa (1986aWesselinowa ( , 1987 calculated the spin-dependent life time r for the acoustic phonons with the summation of two kinds of Hamiltonians H' and HZ, representing respectively the first and second derivatives of the magnetic interaction energy with respect to the lattice displacements. H' and H 2 give the dominant terms in Tj below and above T,, respectively.…”

Section: Efsect Of Spin Ordering On Phonon Dampingmentioning

confidence: 99%

Effects of spin ordering on phonon and plasmon spectra, and dielectric properties in magnetic semiconductors

Wakamura

Arai

1990

Phase Transitions

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Effects of spin ordering on the phonons, plasmons, and dielectric properties have been investigated for many magnetic crystals, such as Cr-spinels, EuX (X = O,S,Se,Te), and fluorite-type compounds. Of these phenomena, the static dielectric constant and Raman scattering have been extensively discussed. However, the dielectric parameters obtained from infrared spectra have not been discussed in spite of observed various phenomena arising from the direct coupling of spin system with phonons or electrons. Furthermore, these microscopic phenomena can be combined with the macroscopic dielectric values with respect to the spin ordering effect. It will ascertain the mechanism of the spin ordering effect on the values. From this point of view, we review the spin-dependent phenomena on the frequencies of TO and LO phonon modes, phonon damping, optical and static dielectric constants, effective charge, and also on plasmon parameters in the spinel type magnetic semiconductors.KEY WORDS: Spin ordering effect, phonon and plasmon, dielectric property, magnetic semiconductor, spinel.

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Section: Efsect Of Spin Ordering On Phonon Dampingmentioning

confidence: 99%

Effects of spin ordering on phonon and plasmon spectra, and dielectric properties in magnetic semiconductors

Wakamura

Arai

1990

Phase Transitions

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“…x is the ion-doping concentration. F and R designate the spin–phonon interaction constants, which are proportional to the first and second derivative of J , respectively [ 45 ].

depends on the distance between the spins, i.e., on the lattice parameters, inverse proportional.…”

Section: The Model and The Methodsmentioning

confidence: 99%

Magnetic, Optical and Phonon Properties of Ion-Doped MgO Nanoparticles. Application for Magnetic Hyperthermia

2023

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The influence of size and doping effects on the magnetization M, phonon ω and band gap energy Eg of MgO nanoparticles is studied using a microscopic model. The room-temperature ferromagnetism is due to surface or/and doping effects in MgO nanoparticles (NPs). The influence of the spin–phonon interaction is discussed. M increases with decreasing NP size. M and Eg can increase or decrease by different ion doping (Co, Al, La, Fe) due to the different strain that appears. It changes the lattice parameters and the exchange interaction constants. We found that MgO NP with size of 20 nm and Fe- or Co-doping concentration x = 0.1 and x = 0.2, respectively, have a Curie temperature TC = 315 K, i.e., they are appropriate for application in magnetic hyperthermia, they satisfy the conditions for that. The energy of the phonon mode ω = 448 cm−1 increases with decreasing NP size. It increases with increasing Co and Fe, or decreases with Sr ion doping.

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Effect of magnon–LA phonon interaction on LA phonon excitation at finite temperature

Cheng

Lin

Shen

2008

Physica Status Solidi (b)

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A magnon–longitudinal acoustic (LA) phonon interaction model is developed on the basis of a two‐dimensional square Heisenberg ferromagnetic system. The LA phonon excitation is studied by Matsubara–Green function theory, and the LA phonon excitation dispersion curves are calculated on the main symmetric lines in Brillouin zone (BZ). It is found that there exists obvious LA phonon hardening. The hardening of LA phonons becomes more evident near the M point of the BZ boundary. The influences of various parameters on LA phonon hardening are also discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Phonon renormalization and damping in a Heisenberg ferromagnet

Cited by 4 publications

References 8 publications

Effects of spin ordering on phonon and plasmon spectra, and dielectric properties in magnetic semiconductors

Effects of spin ordering on phonon and plasmon spectra, and dielectric properties in magnetic semiconductors

Magnetic, Optical and Phonon Properties of Ion-Doped MgO Nanoparticles. Application for Magnetic Hyperthermia

Effect of magnon–LA phonon interaction on LA phonon excitation at finite temperature

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