Exchange Stiffness and Macroscopic Anisotropy in Heisenberg Spin-Glasses
نویسنده
چکیده
The consequences of rotational-symmetry breaking in Heisenberg spin-glasses are studied with use of order parameters which are time-dependent SO(3) rotation matrices. A microscopic derivation of the hydrodynamic "triad" theory, including the effect of small magnetic fields and random anisotropies, is presented. In the mean-field limit the finitetime exchange stiffness and macroscopic anisotropy constants vanish near the transition temperature T~ as (T~T}",p, = 3.
منابع مشابه
Experimental arguments for a non-zero transition temperature in RKKY Heisenberg spin glasses without anisotropy
2014 While the existence of a phase transition at finite Tc is well admitted for Ising spin glasses in 3dimensions, recent theoretical studies have proposed that Tc is zero in Heisenberg spin glasses and that the finite Tc of real systems is induced by the anisotropy. To clear up this question, we analyse the influence of the anisotropy on the critical behaviour and the transition temperature o...
متن کاملSpin anisotropy and slow dynamics in spin glasses.
We report on an extensive study of the influence of spin anisotropy on spin glass aging dynamics. New temperature cycle experiments allow us to compare quantitatively the memory effect in four Heisenberg spin glasses with various degrees of random anisotropy and one Ising spin glass. The sharpness of the memory effect appears to decrease continuously with the spin anisotropy. Besides, the spin ...
متن کاملInfluence of Anisotropy on the Critical Temperature of Metallic Spin Glasses
We analyse the anisotropy dependence of the transition temperature of Q M n and &Mn spin glasses doped with Au or Pt impurities. We discuss the role of anisotropy in the phase transition of RKKY Heisenberg spin glasses. While the existence of a phase transition at finite temperature is well admitted for Ising spin glasses (SG) in 3d 111, Bray et al. 121 have shown from scaling arguments that th...
متن کامل1 N ov 1 99 6 Spin stiffness in the frustrated Heisenberg antiferromagnet
We calculate the spin stiffness of the S = 1 2 frustrated Heisenberg antiferro-magnet directly from a general formula which is evaluated in the Schwinger boson mean-field approximation. Both Néel and collinear ordering are considered. For collinear ordering, we take the anisotropy of this phase into account, unlike previous approaches. For Néel ordering, a detailed study is made of the finite-s...
متن کاملThree Dimensional Heisenberg Spin Glass Models with and without Random Anisotropy
We reexamine the spin glass (SG) phase transition of the ±J Heisenberg models with and without the random anisotropy D in three dimensions (d = 3) using complementary two methods, i.e., (i) the defect energy method and (ii) the Monte Carlo method. We reveal that the conventional defect energy method is not convincing and propose a new method which considers the stiffness of the lattice itself. ...
متن کامل