Structural evolution and magnetic properties of L10-type Mn54.5Al45.5-xGax(x = 0.0, 15.0, 25.0, 35.0, 45.5) phase
Structural evolution and magnetic properties of L10-type Mn54.5Al45.5-xGax(x = 0.0, 15.0, 25.0, 35.0, 45.5) phase
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L10型Mn54.5Al45.5-xGax(x = 0.0, 15.0, 25.0, 35.0, 45.5)相的结构演化及磁性能
DOI：
10.1016/j.jallcom.2016.04.074
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发表时间：
2016
影响因子：
6.2
通讯作者：
Yang J.B.
中科院分区：
文献类型：
--
作者：
Zhao H.;Yang W.Y.;Shao Z.Y.;Tian G.;Zhou D.;Chen X.P.;Xia Y.H.;Xie L.;Liu S.Q.;Du H.L.;Han J.Z.;Wang C.S.;Yang Y.C.;Yang J.B.
采用快淬和退火工艺制备了具有L10结构的金属间化合物Mn54.5Al45.5-xGax（x= 0.0，15.0，25.0，35.0，45.5）。采用X射线衍射、中子粉末衍射和磁性测量等方法对样品的结构和磁性进行了研究。发现Al和Ga原子同时占据1a（0，0，0）和1d（1/2，1/2，1/2）位，并优先占据1d位.结果表明，随着Ga含量的增加，晶格常数略有减小，而c却异常增大，这可能是由于Ga原子在1d位的位置比Al原子大，质量磁化强度从134 emu/g下降到91 emu/g。与Al合金相比，Ga合金的密度较高，5 K时的g从0.0增加到45.5，矫顽力（iHc）值为3.67kOe，最大能量积（BH）为1.67kOe。Mn_（54.5）Al_（30.5）Ga_（15）样品最大可获得2.05 MGOe。L10样品的居里温度（Tc）均高于室温，且由于a-b面铁磁Mn-Mn相互作用的减弱，Tc值从Mn54.5Al45.5的644 K几乎线性地降低到Mn54.5Ga45.5的578 K。所观察到的磁性是根据竞争的铁磁相互作用之间的Mn时刻在规则的1asite和反铁磁耦合与过量的Mn原子占据Ga（1d）网站。
The intermetallic compounds Mn54.5Al45.5-xGax(x= 0.0, 15.0, 25.0, 35.0, 45.5) with L10structure were prepared by melt-spinning and annealing. The structural and magnetic properties were investigated by means of X-ray diffraction, neutron powder diffraction and magnetic measurement. Al and Ga atoms are found to occupy both the 1a(0, 0, 0) and 1d(1/2, 1/2, 1/2) sites and show a preference occupation for the 1dsite. It was found that the lattice parameteraslightly decreases, whilecabnormally increases with the increase of Ga contentx, which can be attributed to the fact that the Ga atom located at the 1dsites is larger than that of Al. The mass magnetization decreases from 134 emu/g to 91 emu/g at 5 K asxincreases from 0.0 to 45.5 due to higher density of the alloys with Ga in comparison to the alloys with Al. A coercivity (iHc) value of 3.67 kOe and the maximum energy product (BH)maxof 2.05 MGOe were obtained for Mn54.5Al30.5Ga15sample. All the L10samples show a Curie temperature (Tc) well above room temperature and the value ofTcdecreases almost linearly from 644 K for Mn54.5Al45.5to 578 K for Mn54.5Ga45.5due to the decrease of ferromagnetic Mn-Mn interaction in thea-bplane. The observed magnetic properties are in accordance with the competing ferromagnetic interactions between Mn moments at the regular 1asite and antiferromagnetic coupling with the excess Mn atoms occupying the Ga (1d) site.