0.9Cu 0.1CoGe 1? x Si x alloys]]>

摘要

AbstractThe structural transition temperatureTtincreases largely with the introduction of Si in Mn0.9Cu0.1CoGe1-xSixalloys due to the enhancement of degree of hexagonal distortion. Thus, the first-order magnetostructural transformation from ferromagnetic orthorhombic to paramagnetic hexagonal phase can be obtained in the range of 0.15?x?SM) value forx?=?0.16 is 10.3?J/kg K at 297?K, which is comparable to or even larger than those of some typical room-temperature magnetocaloric materials. The nature of magnetostructural transition has been studied by different methods, and it is found that the Arrott plots fail to determine the order of phase transition. In contrast, the universal curve of ΔSMis proved to be a more effective criterion to distinguish the order of phase transition. Besides, a linear relationship between -ΔSMand Δμ0His found, and so the -ΔSMvalues for higher field changes can be estimated by linear fitting. Consequently, large MCE induced by magnetostructural transformation suggests that Mn0.9Cu0.1CoGe1-xSixalloys could be promising candidates for room-temperature magnetocaloric materials.Highlights?The martensitic transition temperature increases largely with the introduction of Si.?The first-order magnetostructural transformation is realized when 0.15?x??Large magnetocaloric effect is obtained around room temperature.?The nature of magnetostructural transition is analyzed by different methods.]]>