Magnetization and time dependent effects in ErCo3Ga2

Abstract

Recently, unusual magnetic properties have been reported on the ErCo3Ga2 compound. In this paper, we report on the measurements of magnetization, ac susceptibility, and the time dependence of magnetization on polycrystalline samples of ErCo3Ga2. The field cooled (FC) samples show negative magnetization with a minimum at 25 K in low magnetic fields. The FC magnetization becomes positive above 150 K. The FC and ZFC magnetizations meet at 150 K as the temperature increases. For magnetic fields above 5000 G, the FC and ZFC magnetizations are the same in the entire temperature range from 5 K to 300 K. The ac susceptibility shows a peak around 20 K. We have found that for T < 150 K, the magnetization in a constant magnetic field at constant temperature increases with time and does not attain a constant value over 64 h. The increase in magnetization is linear on the log(time) scale. The magnetic properties suggest a spin glass-type transition below 150 K and a strong temperature dependent magnetic anisotropy.