  (Mn,Fe)2(P,Si) single crystals have been successfully grown by flux method.
Single crystal diffraction demonstrates that Mn0.83Fe1.17P0.72Si0.28
crystallizes in a hexagonal crystal structure (space group P-62m) at both 100
and 280 K, in the ferromagnetic and paramagnetic states, respectively. The
magnetization measurements show that the crystals display a first-order
ferromagnetic phase transition at their Curie temperature (TC). The preferred
magnetization direction in is along the c axis. A weak magnetic anisotropy of
K1 = 0.25x106 J/m3 and K2 = 0.19x106 J/m3 is found at 5 K. These values
indicate a soft magnetic behaviour favourable for magnetic refrigeration. A
series of discontinuous magnetization jumps is observed far below TC by
increasing the field at a constant temperature. These magnetization jumps are
irreversible, occur spontaneously at constant temperature and magnetic field,
but can be restored by cycling across the first-order phase transition.
