Abstract

Mn_xSi_{1 – x} (x ≈ 0.5) thin films have been produced on c- and r-cut sapphire substrates by the droplet-free pulsed laser deposition method at various laser energy densities E on the target. Their magnetic, electric, and X-ray diffraction properties as a function of E and substrate orientation have been investigated. It has been established that the high-temperature ferromagnetic phase in the films at E ≥ 6 J cm^–2 is more pronounced than that at E ≈ 4–5 J cm^–2, when the low-temperature ferromagnetic phase dominates and there is no influence of the sapphire substrate orientation. The attained Curie temperature T_C was 330 K at E ≈ 7.4 J cm^–2 for the Mn_xSi_{1 – x} films produced on c- and r-cut sapphire substrates. The magnetization of the Mn_xSi_{1 – x} films produced at E ≥ 6 J cm^–2 on c-cut sapphire is higher than that on r-cut sapphire and, conversely, lower when E ≤ 5.5 J cm^–2. A change in the ratio of the diffuse signal amplitudes in the X-ray spectra for the films grown on different substrates is also observed under these conditions. Such a correlated behavior with magnetization is explained by the existence of ε-MnSi nanocrystallites of optimal sizes, which, on the one hand, are responsible for the emergence of a diffuse signal in the X-ray spectra and, on the other hand, determine the high-temperature ferromagnetism of the films. The concentration of such nanocrystallites and the distribution of defects in the films are controlled by the type of substrate and the energy density on the target.

中文翻译：

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激光能量密度随目标变化而变化，在c和r形切割蓝宝石衬底上通过激光合成产生Mn x Si 1 – x（x≈0.5）薄膜的铁磁性

摘要

锰_X的Si _{1 - X}（X ≈0.5）薄膜已生产上Ç -和- [R -馏分蓝宝石衬底通过在不同的激光能量的自由微滴脉冲激光沉积法密度Ë上的目标。已经研究了它们的磁，电和X射线衍射特性随E和衬底方向的变化。已经确定的是，在膜的高温铁磁相ë ≥6,7-厘米^-2比这更明显在Ë ≈4-5Ĵ厘米^-2在低温铁磁相占主导地位时，蓝宝石衬底取向没有影响。达到的居里温度Ť _Ç在330ķ Ë ≈7.4Ĵ厘米^-2为Mn的_X的Si _{1 - X}上产生薄膜Ç -和- [R -馏分蓝宝石衬底。中的Mn的磁化_X的Si _{1 - X}在生产的膜Ë ≥6,7-厘米^-2上Ç -cut蓝宝石是高于ř -cut蓝宝石和，相反地，较低时È ≤5.5Ĵ厘米^-2。在这些条件下，还可以观察到在不同基板上生长的薄膜的X射线光谱中的漫射信号幅度之比的变化。这种与磁化强度相关的行为可以通过存在最佳尺寸的ε-MnSi纳米晶体来解释，该晶体一方面导致X射线光谱中出现散射信号，另一方面确定薄膜的高温铁磁性。此类纳米微晶的浓度和膜中缺陷的分布由基材的类型和靶材上的能量密度控制。