Coherent magnon dynamics in ferromagnetic models with nonuniform magnetic field and correlated disorder

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:410

Article

Nunes, D. M.¹  Ranciaro Neto, A.^1,2  de Moura, F. A. B. F.¹ 

[1] Univ Fed Alagoas, Inst Fis, BR-57072970 Maceio, AL, Brazil

[2] Fac Econ Adm & Contabilidade, Ave Lourival Melo Mota S-N,Bl 14, BR-57072970 Tabuleiro Dos Martins, Brazil

关键词: Disordered systems;    Phase transitions;    Spin dynamics;    Quantum localization;   

DOI  :  10.1016/j.jmmm.2016.03.026

来源: Elsevier

【 摘 要 】

In this work we investigated the nature of the one-magnon eigenstates in a disordered chain at the presence of a non-uniform magnetic field. In our study, we analyzed the one-dimensional ferromagnetic Heisenberg model within the one-magnon framework. The spin-spin interaction was considered as a correlated disorder distribution with power law spectrum S(k) alpha K-alpha. By using numerical methods we calculated the time evolution of a initially localized Gaussian wave-packet. Our results reveal that for weak correlations (alpha < 1), the magnetic wave-packet remains localized around the initial position and for alpha > 1, we got an oscillatory profile similar to the Bloch-like phenomenology. We calculate the frequency of these oscillations and observed that it is in a good agreement with the semi-classical approach traditionally used to explain the Block-like oscillatory behavior. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free