Effect of Fe addition on microstructure and magnetocaloric effect in Gd5SixGe3.9−xFe0.1 alloys with varying Si/Ge ratio

The Gd5SixGe3.9−xFe0.1 alloys (x = 1.8-2.1) alloys exhibited a first-order magnetic phase transition with hysteresis of 8-13 K upon heating and cooling. Microstructural studies revealed that the alloys were comprised of monoclinic Gd5Si2Ge2-type phase with small fraction of the Gd5Si3-type and FeSi-rich minor phases. The hysteresis losses are significantly reduced in the x = 2.1 alloy due to the absence of field-induced phase transition.