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通过结构和磁性测量,研究了Ni50-xCoxMn39Sn11(x=0,2,4,6)Heusler合金的晶体结构、相变和磁性.结果表明,随Co含量增加,该系列合金的马氏体相变温度明显下降,而Curie温度却呈现出上升的趋势,并在室温下展现出不同的晶体结构.同时,Co含量的增加导致样品在奥氏体相的磁性迅速增加,而马氏体相的磁性却几乎保持不变,显著地提高了2相之间的磁化强度差异(ΔM).特别是当Co含量增加到x=4时,2相之间的ΔM达到40 Am2/kg,并表现出磁场驱动马氏体相变的特征.此外,还研究了Ni50-xCoxMn39Sn11(x=0,2,4)样品在马氏体相变过程中的应变行为.其中,x=4样品的相变应变量达到了0.17%,通过3 T的磁场循环,该样品在215~235 K的温度范围均显示出可回复磁感生应变.这种可回复的应变行为可归因于样品中的部分马氏体相变可由等温磁场驱动.
The crystal structure, phase transition and magnetic properties of Ni50-xCoxMn39Sn11 (x = 0, 2, 4, 6) Heusler alloy were studied by means of structure and magnetic measurements.The results show that with the increase of Co content, the martensitic transformation But the Curie temperature shows a rising trend and shows different crystal structures at room temperature.At the same time, the increase of Co content leads to the rapid increase of the magnetic property of the sample in the austenite phase, while the magnetic property of the martensite phase But remained almost unchanged, significantly increasing the difference in magnetization between the two phases (ΔM). Especially when the Co content is increased to x = 4, the ΔM between the two phases reaches 40 Am 2 / kg and shows a magnetic field Driven martensite transformation.In addition, the strain behavior of Ni50-xCoxMn39Sn11 (x = 0, 2, 4) samples during the martensitic transformation was also investigated, in which the phase transformation strain of x = 4 Reached 0.17% and the sample reverted to magnetisensitive strain at a temperature range of 215-235 K through 3 T magnetic field cycling.The recoverable strain behavior can be attributed to the fraction of martensite in the sample Phase changes can be driven by an isothermal magnetic field.