Dynamic scaling and aging phenomena in a short-range Ising spin glass: Cu0.5Co0.5Cl2-FeCl3 graphite bi-intercalation compound

Article

关键词: MAGNETIC PHASE-TRANSITIONS;    ORDERED PHASE;    EQUILIBRIUM;    BEHAVIOR;    FIELD;    FE0.5MN0.5TIO3;    RELAXATION;    SYSTEM;    ENERGY;    MODEL;   

DOI  :  10.1103/PhysRevB.68.094424

来源: SCIE

【 摘 要 】

Static and dynamic behavior of short-range Ising spin glass (SG) Cu0.5Co0.5Cl2-FeCl3 graphite bi-intercalation compounds has been studied with superconducting quantum interference device dc and ac magnetic susceptibility. The T dependence of the zero-field relaxation time tau above a spin-freezing temperature T-g(=3.92+/-0.11 K) is well described by critical slowing down. The absorption chi(') below T-g decreases with increasing angular frequency omega, which is in contrast to the case of 3D Ising spin glass. The dynamic freezing temperature T-f(H,omega) at which dM(FC)(T,H)/dH=chi(')(T,H=0,omega) is determined as a function of frequency (0.01 Hz less than or equal toomega/2piless than or equal to1 kHz) and magnetic field (0less than or equal toHless than or equal to5 kOe). The dynamic scaling analysis of the relaxation time tau(T,H) defined as tau=1/omega at T=T-f(H,omega) suggests the absence of SG phase in the presence of H (at least above 100 Oe). Dynamic scaling analysis of chi(')(T,omega) and tau(T,H) near T-g leads to the critical exponents (beta=0.36+/-0.03, gamma=3.5+/-0.4, nu=1.4+/-0.2, z=6.6+/-1.2, psi=0.24+/-0.02, and theta=0.13+/-0.02). The aging phenomenon is studied through the absorption chi(')(omega,t) below T-g. It obeys a (omegat)(-b') power-law decay with an exponent b(')approximate to0.15-0.2. The rejuvenation effect is also observed under sufficiently large (temperature and magnetic-field) perturbations.

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