We report the structural and magnetic behavior of single phase inverse Heusler alloys Cr₂Co_(1−x)Cr_xAl (x = 0, 0.2, and 0.4) by using x-ray diffraction (XRD), Raman spectroscopy, isothermal magnetization, and magnetic susceptibility measurements. Interestingly, the Rietveld refinement of XRD data with space group I$\overline{4}m2$ reveal a tetragonal distortion with a c/a ratio around 1.38 in these inverse Heusler structures. The bulk compositions have been confirmed by energy dispersive x-ray spectroscopy measurements. The active Raman mode F_2g is observed at 320 cm⁻¹, which confirms the X-type Heusler structure, as the A2 and B2 type structures are known to be not Raman active. The area of F_2g mode decreases with an increase in the Cr concentration, which indicates that the origin of this mode is due to Co vibrations. The isothermal magnetization data confirm the magnetic moment to be close to zero (≤0.02 μ_B/f.u.) at ≈70 kOe and the negligible coercive field suggests the fully compensated ferrimagnetic nature of these samples. The susceptibility behavior indicates irreversibility between zero-field and field-cooled curves and complex magnetic interactions at low temperatures.

中文翻译：

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Cr2Co（1-x）CrxAl逆荷斯勒合金的结构和磁行为

我们通过使用X射线衍射（XRD），拉曼光谱，等温磁化强度报告了单相反霍斯勒合金Cr ₂ Co _{（1- x）} Cr _x Al（x = 0、0.2和0.4）的结构和磁性行为，和磁化率测量。有趣的是，空间群I的XRD数据的Rietveld细化$\overline{4}米2$在这些逆荷斯勒结构中发现ac / a比率约为1.38的四方畸变。本体组合物已经通过能量色散X射线光谱测量法确认。在320cm ^-1处观察到活性拉曼模式F _{2 g}，这证实了X型霍斯勒结构，因为已知A2和B2型结构不是拉曼活性的。F _{2 g}模式的面积随Cr浓度的增加而减小，这表明该模式的起源是由于Co振动。等温磁化数据确认的磁矩为接近零（≤0.02 μ_乙/ ˚F。ü。）在≈70 kOe时，矫顽场可以忽略不计，表明这些样品的铁磁性质得到了完全补偿。磁化率行为表明零场和场冷曲线之间的不可逆性以及低温下复杂的磁相互作用。