Generalized approach to non-exponential relaxation

Pramana

R M Pickup²  P Fouquet³  B Farago³  C Pappas2⁴  R Cywinski²  P Falus¹ 

[1] $$;School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK$$;Institut Laue-Langevin, 6, Rue Jules Horowitz, 38042 Grenoble, France$$;Hahn-Meitner Institut, Glienicker Straße 100, 14109 Berlin, Germany$$

关键词: Neutron scattering;    magnetic systems.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

Non-exponential relaxation is a universal feature of systems as diverse as glasses, spin glasses, earthquakes, financial markets and the universe. Complex relaxation results from hierarchically constrained dynamics with the strength of the constraints being directly related to the form of the relaxation, which changes from a simple exponential to a stretched exponential and a power law by increasing the constraints in the system. A global and unified approach to non-exponentiality was first achieved by Weron and was further generalized by Brouers and Sotolongo-Costa, who applied the concept of non-extensive entropy introduced by Tsallis to the relaxation of disordered systems.These concepts are now confronted with experimental results on the classical metallic spin glasses CuMn, AuFe and the insulating system EuSrS. The revisited data have also be complemented by new results on several compositions of the classical CuMn spin glass and on systems, like CoGa and CuCo, the magnetic behaviour of which is believed to arise from magnetic clusters and should be characteristic for superparamagnetism.

【 授权许可】

Unknown