Král Daniel, Beran Lukáš, Zelený Martin, Zemen Jan, Antoš Roman, Hamrle Jaroslav, Zázvorka Jakub, Rameš Michal, Onderková Kristýna, Heczko Oleg, Veis Martin
Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12 16 Prague 2, Czech Republic.
Faculty of Mechanical Engineering, Institute of Materials Science and Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno, Czech Republic.
Materials (Basel). 2020 Feb 4;13(3):703. doi: 10.3390/ma13030703.
FeMnGa Heusler-like compounds were investigated in a wide range of Fe/Ga ratios while keeping the Mn content constant and equal 25 at% in order to elucidate the interplay between magnetic properties and composition. Materials were prepared by arc-melting from pure elements and subsequently annealed. Experimental investigations were focused on magnetization behavior in a wide temperature range from 4 to 1000 K and magnetic field up to 9 T. Optical and magneto-optical (MO) measurements were employed to shed more light on the magnetic state and electronic structure of investigated materials. Magnetization measurements indicated that in the vicinity of stoichiometry (FeMnGa) the compounds are ferro/ferrimagnetic, whereas the Fe-deficient compound is paramagnetic and at high Fe concentration the antiferromagnetic interaction prevails. Theoretical calculations of corresponding ordered and disordered stoichiometric compounds were carried out and compared to the experiment on the level of net magnetic moment as well as magneto-optical spectra. This comparison suggests that the Heusler crystal structure, L2, is not present even close to stoichiometry. Moreover, the comparison of density of states (DOS) for ordered and disordered structures allowed us to explain missing martensitic transformation (MT) in investigated materials.
在保持锰含量恒定且等于25原子百分比的情况下，对不同铁/镓比例范围的类赫斯勒化合物FeMnGa进行了研究，以阐明磁性能与成分之间的相互作用。材料由纯元素通过电弧熔炼制备，随后进行退火处理。实验研究集中在4至1000K的宽温度范围和高达9T的磁场下的磁化行为。采用光学和磁光（MO）测量来进一步了解所研究材料的磁态和电子结构。磁化测量表明，在化学计量比（FeMnGa）附近，化合物为铁磁/亚铁磁性，而缺铁化合物为顺磁性，在高铁浓度下反铁磁相互作用占主导。对相应的有序和无序化学计量化合物进行了理论计算，并在净磁矩和磁光光谱水平上与实验进行了比较。这种比较表明，即使接近化学计量比，赫斯勒晶体结构L2也不存在。此外，对有序和无序结构的态密度（DOS）进行比较，使我们能够解释所研究材料中缺失的马氏体相变（MT）。
