Successive inverse and normal magnetocaloric effects in HoFeSi compound

Magnetic properties and magnetocaloric effect (MCE) of HoFeSi compound have been studied systematically. HoFeSi compound undergoes two successive magnetic phase transitions with the variation of temperature: a paramagnetic to ferromagnetic (FM) transition around TC =29 K followed by an FM to antiferromagnetic (AFM) or ferrimagnetic (FIM) transition at Tt = 20 K. The field dependence of magnetization reveals that a field-induced AFM/FIM-FM metamagnetic transition occurs below Tt with the increase in magnetic field. For a relatively low field change of 2 T, successive inverse and normal MCEs are observed and the maximum ΔSM values reach as high as 5.6 and 7.1 J/kg K around Tt and TC, respectively. This feature of successive inverse and normal MCEs in HoFeSi are suggested to be applied in some magnetic refrigerators with special designs and functions.