Temperature dependence of the spin susceptibility of nearly ferromagnetic Fermi systems

Mishra, S. G. ; Ramakrishnan, T. V. (1978) Temperature dependence of the spin susceptibility of nearly ferromagnetic Fermi systems Physical Review B: Condensed Matter and Materials Physics, 18 (5). pp. 2308-2317. ISSN 1098-0121

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Official URL: http://prb.aps.org/abstract/PRB/v18/i5/p2308_1

Related URL: http://dx.doi.org/10.1103/PhysRevB.18.2308

Abstract

The spin susceptibility of nearly ferromagnetic Fermi systems, e.g., liquid 3He, Pd, Ni3Ga is large (X0XPauli−10−1≫1) and varies strongly with temperature on a scale much smaller than the Fermi temperature. A theory for this is presented here. Using a functional transformation, the thermodynamic potential of the fermion system is converted to that of interacting spin fluctuations (a vector-boson field). The parameters of the latter are determined by the fermion system. The susceptibility is related to the spinfluctuation self-energy Σ. From a diagrammatic analysis of Σ , we show that there exists a convergent expansion for its temperature-dependent part, in terms of the number of correlated internal thermal spin fluctuations. The leading terms have one or two internal spin fluctuations: the three-spin-fluctuation term is of higher order in Τ/α0 (for Τ≪ α0) and in Τ (for α0≲ Τ≪ 1). (Here Τ=T/TF0.) Thus a calculation of X−1(Τ)XP=α (Τ) is possible in the entire degenerate range Τ≪ 1, and not merely the paramagnon range Τ≪ α 0. α(Τ) is shown to go as α0+A(Τ20) for Τ≪ α0 and as α0+BΤ for α0≲Τ≪ 1, and interpolates smoothly between these two limits. (A and B are constants.) The former is the paramagnon-theory result and the latter is the result for "classical" spin fluctuations. As an illustration, we calculate, with one adjustable parameter, α(Τ) for liquid 3He in the temperature range 0<Τ≲0.2. The agreement with experiment is very good.

Item Type:Article
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ID Code:40815
Deposited On:25 May 2011 11:00
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