A method for decreasing the minimum temperature achievable by a SQUID magnetometer is presented, based on adiabatic demagnetisation refrigeration. The method is found to successfully provide cooling to below 0.26 K for more than an hour. However, performing magnetisation measurements strongly influences the temperature and shortens the duration to a few minutes in the original setup. The cause is most probably re-evaporation of condensed helium, and possible improvements to prevent this effect are suggested.