The roles of spin wave and phonon in the temperature dependence of magnetization in an itinerant electron ferromagnet

1996 ◽  
Vol 219-220 ◽  
pp. 115-117 ◽  
Author(s):  
Ikuya Yoshida ◽  
D.J. Kim
1974 ◽  
Vol 52 (8) ◽  
pp. 704-707 ◽  
Author(s):  
D. M. Edwards

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.


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 .


1993 ◽  
Vol 07 (01n03) ◽  
pp. 504-507
Author(s):  
N. GARCIA ◽  
A. LEVANYUK ◽  
P. SERENA

Using the low-temperature perturbation (spin wave) theory we calculate the temperature dependence of anisotropy constant, spin-wave stiffness, spontaneous magnetization for a two-dimensional ferromagnetic Heisenberg model with various types of anisotropy and interactions. We found that the Polyakov renormalization procedure is inapplicable for ferromagnetic phase at any anisotropy. We did not find the reorientation phase transition due to dipole-dipole interaction predicted by Pescia and Pokrovsky. Taking into account the spin flips we obtained a phase transition temperature in good agreement with results of our Monte Carlo calculations. These results demonstrate also the effectiveness of the spin wave theory.


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