Temperature Dependence of the Spin‐Wave Energy in the Itinerant Electron Model of Ferromagnetism

1968 ◽  
Vol 39 (2) ◽  
pp. 475-475 ◽  
Author(s):  
J. Mathon ◽  
E. P. Wohlfarth
Keyword(s):  
Temperature Dependence ◽  
Spin Wave ◽  
Wave Energy ◽  
Itinerant Electron ◽  
Electron Model

The temperature dependence of the spin wave energy in the itinerant electron model of ferromagnetism

1968 ◽  
Vol 302 (1470) ◽  
pp. 409-418 ◽  
Keyword(s):  
Spin Wave ◽  
Wave Energy ◽  
Short Range ◽  
Distribution Functions ◽  
Itinerant Electron ◽  
Short Range Interaction ◽  
Range Interaction ◽  
Electron Model ◽  
Long Wavelength ◽  
Chemical Potentials

The long wavelength non-interacting spin wave energy for metals at low temperatures is expressed as ћω q = Dq 2 = ( D 0 + D 1 T 2 ) q 2 . The dependence of the coefficient D 1 on the density of states function, the number of electrons per atom, n , and the effective short range interaction energy, I , is discussed. The variation of D with T 2 comes from the change with temperature of the relative occupation ζ and the chemical potentials of the ± spin sub-bands as well as from the direct asymptotic expansion of the Fermi distribution functions occurring in the expression for D .

Temperature Dependence of the Exchange Splitting in Ferromagnetic Metals II. The Study of Stoner Excitations by the de Haas–van Alphen Effect

1974 ◽  
Vol 52 (8) ◽  
pp. 704-707 ◽  
Author(s):  
D. M. Edwards
Keyword(s):  
Temperature Dependence ◽  
Spin Wave ◽  
Itinerant Electron ◽  
Exchange Splitting ◽  
Ferromagnetic Metals

It is shown that the de Haas–van Alphen (dHvA) effect in ferromagnetic metals can give information about the Stoner T2 term in the temperature dependence of the magnetization, without interference from spin wave contributions. In particular, the temperature dependence of the dHvA frequency for a very weak itinerant electron ferromagnet could distinguish clearly between conflicting theories of these materials.

Spin wave resonance in iron

1966 ◽  
Vol 292 (1429) ◽  
pp. 224-239 ◽  
Keyword(s):  
Spin Wave ◽  
Wave Interaction ◽  
Growth Conditions ◽  
Itinerant Electron ◽  
Coupling Constant ◽  
Iron Films ◽  
Electron Model ◽  
Spin Wave Resonance ◽  
Logarithmic Plot ◽  
Wave Resonance

The spin wave spectra obtained from thin films of the iron group metals are discussed, mainly with reference to the spectrum of iron. It is found that, under suitable growth conditions, specimens can be manufactured whose resonance absorption modes are very similar to those predicted by the simple model of spin wave resonance. Three iron films are examined whose thicknesses range from 1800 to 4200 Å and all give similar values for the spin wave coupling constant D . The constant D is examined as a function of temperature and is found to behave in a similar way to nickel and cubic cobalt, giving a 10 % variation of D between 20 and 300 °K. A logarithmic plot indicates that a T5/2 law is obeyed for most of the temperature range, but it is also possible to fit the points to a T 2 plot, in accord with the itinerant electron model, provided other power law terms are assumed present. These other terms might be the spin wave interaction T5/2 term or that due to the effect of thermal expansion. The linewidths observed in the iron resonances are discussed, and reasons based on the ineffectiveness of the two magnon scattering processes are put forward for these narrow lines ( ~ 37 Oe) as opposed to the much broader lines often found in ferromagnetic resonance.

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