中文摘要：

为了研究Co空位对Mn_3CoN化合物磁性质和热膨胀性能的影响,采用固相烧结法制备了名义配比为Mn_3Co_（1-x）N（x=0,0.1,0.2,0.3）的反钙钛矿结构化合物,并研究了该类化合物的晶格、磁转变和热膨胀性能。结果表明：所有的样品均显示出2个磁转变点;随着x的增加,低温磁转变点往高温移动,高温磁转变点往低温移动;同时,所有的样品中都发现了反常热膨胀行为,包括低于270K的低热膨胀和270K附近的负热膨胀;低热膨胀区间的线膨胀系数随着x的增加而呈现出减小的趋势;值得注意的是,当x=0.3时,样品在100~240 K温度区间内显示出近零热膨胀行为,其热膨胀系数α=9.70×10~（-7） K~（-1）;Mn_3Co_（1-x）N化合物中的反常热膨胀行为可能是磁体积效应所致。

英文摘要：

The antiperovskite compounds with nominal composition Mn_3Co_（1-x）N（x=0,0.1,0.2and 0.3）were synthesized,and the lattices,magnetic and thermal expansion characteristics of these compounds were investigated in this paper.The results show that all the compounds show two magnetic transitions,which could be tuned by Co contents.Moreover,the low thermal expansion and negative thermal expansion behaviors were observed in these samples.For the low thermal expansion behavior,the thermal expansion coefficient（α）decreases with the increasing of x.It is a remarkable fact that theαis 9.70×10~（-7） K~（-1）（100-240K）for x=0.3,indicating that the nearly zero thermal expansion behavior could be obtained with optimizing the Co content.The abnormal thermal expansion behaviors were also discussed based on the magnetovolume effect.