The adiabatic temperature change ΔTad of a Mn1:3Fe0:7P0:5Si0:55 Fe2P-type
alloy was measured under different magnetic field-sweep rates from 0:93 Ts-1 to
2870 Ts-1. We find a field-sweep-rate independent magnetocaloric effect due a
partial alignment of magnetic moments in the paramagnetic region overlapping
with the magnetocaloric effect of the first-order phase transition. Additionally,
the first-order phase transition is not completed even in fields up to 20T leading
to a non-saturating behavior of ΔTad. Measurements in different pulsed fields
reveal that the first-order phase transition cannot follow the fast field changes as
previously assumed, resulting in a distinct field-dependent hysteresis in ΔTad.
