Rate dependence of the magnetocaloric effect in La-Fe-Si compounds

The dynamic magnetocaloric effect in La(Fe sub(x)Co sub(y)Si sub(1-x-y)) sub(13) with x=0.9 and low Co content of y=0.015 was analysed by calorimetrie measurements at constant magnetic field and constant temperature as well as magnetisation relaxation measurements. It is shown that the rate dependence of the measurement, which leads to an increased entropy hysteresis with increasing rate of the driving force (temperature or magnetic field), can be mainly attributed to a thermal contact resistance R between sample and thermal bath of the measurement setup.