Dynamic scaling and aging phenomena in a short-range Ising spin glass:Cu0.5Co0.5Cl2−FeCl3graphite bi-intercalation compound
| Autor: | Masatsugu Suzuki, Itsuko S. Suzuki |
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| Rok vydání: | 2003 |
| Předmět: | |
| Zdroj: | Physical Review B. 68 |
| ISSN: | 1095-3795 0163-1829 |
| Popis: | Static and dynamic behavior of short-range Ising spin glass (SG) Cu 0 . 5 Co 0 . 5 Cl 2 -FeCl 3 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 τ above a spin-freezing temperature T g ( = 3.92′0.11 K) is well described by critical slowing down. The absorption Χ" below T g decreases with increasing angular frequency ω, which is in contrast to the case of 3D Ising spin glass. The dynamic freezing temperature T f (H,w) at which dM F C (T,H)/dH=Χ'(T,H=0,ω) is determined as a function of frequency (0.01 Hz ≤ ω/2π≤1 kHz) and magnetic field (0≤H≤5 kOe). The dynamic scaling analysis of the relaxation time τ(T,H) defined as r= 1/ω at T = T f (H,ω) suggests the absence of SG phase in the presence of H (at least above 100 Oe). Dynamic scaling analysis of Χ"(T,ω) and r(T,H) near T g leads to the critical exponents (β=0.36′0.03, γ=3.5′0.4, v= 1.4′0.2, z=6.6′1.2, ψ=0.24′0.02, and θ=0.13′0.02). The aging phenomenon is studied through the absorption Χ"(ω,t) below T g . It obeys a (ωt) - b " power-law decay with an exponent b"0.15-0.2. The rejuvenation effect is also observed under sufficiently large (temperature and magnetic-field) perturbations. |
| Databáze: | OpenAIRE |
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