相关论文: Exponent 1/4 from the mean field approximation
Recent developments in spintronics have drawn renewed attention to the spin dynamics of cubic ferromagnetic crystals EuO and EuS. These ferromagnets have the simplest possible magnetic structure, making them the most suitable systems for…
We experimentally investigate the magnetization angle dependence $M(\alpha)$ for single crystals of MnTe altermagnetic candidate. In high magnetic fields, experimental $M(\alpha)$ curves mostly reflect standard antiferromagnetic spin-flop…
The paper proposes an approximate expression for calculating very complex one-dimensional integrals depending on the parameter $a$. These integrals often occur in computational problems theory of magnetic solitons. The resulting analytical…
We calculate the low-temperature thermodynamic quantities (magnetization, correlation functions, transverse and longitudinal correlation lengths, spin susceptibility, and specific heat) of the frustrated one-dimensional spin-half J1-J2…
The spin-1/2 Heisenberg model is formulated in terms of a mean-field approximation (MFA) by using the matrix forms of spin operators $\hat{S}_x,\hat{S}_y$ and $\hat{S}_z$ in three-dimensions. The considered Hamiltonian consists of bilinear…
At finite temperature we study the quantum tunneling of magnetization for a small ferromagnetic particle with the biaxial symmetry placed in a magnetic field at an arbitrary angle. We present numerical WKB exponent below the crossover…
The low Curie temperature (T_C approx 28K) and small ordered moment (M_0 approx 0.17 mu_B f.u.^-1) of ZrZn2 make it one of the few examples of a weak itinerant ferromagnet. We report results of susceptibility, magnetization, resistivity and…
We present a detailed study, within the mean-field approximation, of an impurity band model for III-V diluted magnetic semiconductors. Such a model should be relevant at low carrier densities, below and near the metal-insulator transition.…
We formulate a theory of doped magnetic semiconductors such as Ga$_{1-x}$Mn$_x$As which have attracted recent attention for their possible use in spintronic applications. We solve the theory in the dynamical mean field approximation to find…
In this work, we explore some interesting details of the time-dependent regime of the long-range systems under mean-field approximation in comparison with the critical dynamics of the short-range systems. First, we discuss some mechanisms…
Results of a study of dc-magnetization M(T, H), performed on a Nd0.6Pb0.4MnO3 single crystal in the temperature range around T_C (Curie temperature) which embraces the critical region | epsilon | = |T -T_C |/T_C <= 0.05 are reported. The…
A holographic realization for ferromagnetic systems has been constructed. Owing to the holographic dictionary proposed on the basis of this realization, we obtained relevant thermodynamic quantities such as magnetization, magnetic…
We use the mean-field approximation to simplify the master equation for sympathetic cooling of Bosons. For the mean single-particle occupation numbers, this approach yields the same equations as the factorization assumption introduced in an…
We use bosonization to derive the effective field theory that properly describes ferromagnetic transition in one-dimensional itinerant electron systems. The resultant theory is shown to have dynamical exponent z=2 at tree leve and upper…
Three dimensional neutron depolarization measurements have been carried out on single-crystalline UGe2 between 4 K and 80 K in order to determine the average ferromagnetic domain size d. It is found that below T_C = 52K uniaxial…
Motivated by a recent proposal of a Bethe approximation for the triangular Ising antiferromagnet [Phys. Rev. B {\bf 56}, 8241 (1997)], which seems to predict a disordered phase at any temperature in zero field, we analyze in some detail…
The sequence of prominent fractional quantum Hall states up to $\nu$=5/11 around $\nu$=1/2 in a high mobility two-dimensional electron system confined at oxide heterointerface (ZnO) is analyzed in terms of the composite fermion model. The…
In pulsed magnetic fields up to 65T and at temperatures below the N\'eel transition, our magnetization and magnetostriction measurements reveal a field-induced metamagnetic-like transition that is suggestive of an antiferromagnetic to…
We present numerical simulations of the random field Ising model in three dimensions at zero temperature. The critical exponents are found to agree with previous results. We study the magnetic susceptibility by applying a small magnetic…
It is demonstrated how the correction factor alpha used in Hall magnetometry of localized magnetic field profiles depends on the sample geometry and on the electron mean free path, in the quasi-ballistic and ballistic regimes, for weak and…