The effects of Ta substitution on the first-order phase transition have been firstly studied in Hf_1-xTa_xFe₂ (x = 0.15, 0.165, 0.18) alloys with kagome-type lattice. Higher Ta substitution leads to the reduced metamagnetic transition temperature (T_t) from low-temperature ferromagnetism to high-temperature antiferromagnetism and paramagnetism. By doping C atoms, the T_t is gradually reduced and thermal hysteresis becomes widened in the alloys with higher Ta substitution. The critical field which triggers the metamagnetic phase transition is not substantially affected by interstitial C atoms. With increased Ta substitution, for the field change of 7 T, the maximum of magnetic entropy change (ΔS^max) of 3.7 J kg⁻¹ K⁻¹ is obtained at x = 0.15 and enhanced to 4 J kg⁻¹ K⁻¹ at x = 0.165 but reduced to ~ 3.21 J kg⁻¹ K⁻¹ in Hf_0.82Ta_0.18Fe₂ alloy. By C addition, both T_t and the temperature where ΔS is maximized are shifted to a lower temperature, especially in the higher Ta-contained alloys.

首先研究了 具有Kagome型晶格的Hf _{1- x} Ta _x Fe ₂（x = 0.15，0.165，0.18）合金中Ta取代对一阶相变的影响。较高的Ta置换量导致从低温铁磁性到高温反铁磁性和顺磁性的亚磁转变温度（T _t）降低。通过掺杂C原子，T _tTa取代度较高的合金中，Al逐渐降低，热滞变宽。触发超磁相变的临界场基本上不受间隙C原子的影响。随着Ta置换的增加，对于7 T的磁场变化，在x  = 0.15时可获得3.7 J kg ^-1  K ^-1的最大磁熵变（ΔS ^max），并增强到4 J kg ^-1  K ^-1在x  ＝ 0.165时，但在Hf _0.82 Ta _0.18 Fe ₂合金中降低至〜3.21J kg ^-1  K ^-1。通过C加法，两个T_t和ΔS最大化的温度会移至较低的温度，尤其是在含Ta较高的合金中。