Thermally activated magnetization reversal processes become manifest in the dependence of the remanent coercivity on the time during which a magnetic field is applied opposite to the initial magnetization direction. They have important consequences for the long term stability and short time writeability of future high density recording media. In this paper, we report on a new experiment using a contact write/read tester to study the time dependence of the remanent coercivity over more than 10 orders of magnitude (from 6 ns to >60 s). Remanence coercivity and signal decay measurements of a CoPtCr recording medium with 5.5 nm thickness are presented. (C) 1999 American Institute of Physics. [S0021-8979(99)62908-5].