Abstract
The time decay of the isothermal magnetization of tetrakis-dimethylaminoethylene (TDAE)- after switching off a small external magnetic field has been studied between 20 and 4 K. Below a remanent magnetization —representing the fraction of the frozen out spins—that becomes unobservably small above 12 K has been found. The relaxing magnetization fraction component , on the other hand, increases as is approached from below. The time decay of the magnetization is rather slow below and can be described by a stretched exponential form M(t)=+exp[-(t/τ]. The exponent α decreases from 0.14 at 4 K to 0.08 at 12 K. This shows that the spectrum of relaxation times slowly changes with temperature and becomes very wide as is approached from below. No slowly relaxing component is found above . The above features are characteristic of a spin-glass-like freezing process.
- Received 31 May 1994
DOI:https://doi.org/10.1103/PhysRevB.50.13051
©1994 American Physical Society