Non-stoichiometry and Antiferromagnetic Phase Transition of NaCl-type CrN Thin Films Prepared by Reactive Sputtering
Non-stoichiometry and Antiferromagnetic Phase Transition of NaCl-type CrN Thin Films Prepared by Reactive Sputtering
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DOI：
10.2320/matertrans1989.37.121
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发表时间：
1996-02
期刊：
影响因子：
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通讯作者：
Y. Tsuchiya;K. Kosuge;Yasukuni Ikeda;T. Shigematsu;S. Yamaguchi;N. Nakayama
中科院分区：
文献类型：
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作者：
Y. Tsuchiya;K. Kosuge;Yasukuni Ikeda;T. Shigematsu;S. Yamaguchi;N. Nakayama
在Ar/N2混合气体中，用反应溅射法制备了NaCl型非化学计量比CrN 1+x（0.0 ≤x≤ 0.2）薄膜。在总压为0.67 Pa、氮气混合比为20%的条件下，获得了接近化学计量比的CrN薄膜。磁化率、电阻率和X射线衍射测量表明，这些薄膜在260 K附近出现反铁磁一级相变。随着N2分压的增加，得到了亚稳态的过化学计量比CrN 1+x薄膜。在纯N2气中制备的样品的组成几乎是CrN 1.2和晶格常数是2%以上的近化学计量的散装CrN。过化学计量比的CrN 1+x薄膜没有出现一级反铁磁相变。它们的X-T曲线在90 K附近有一个宽的极大值。室温电阻率随氮含量的增加而降低，电阻率温度系数始终为负值。磁和电性能的组成依赖性与XPS检测到的费米能级附近的态密度的变化相关。
Non-stoichiometric CrN 1+x (0.0≤x≤0.2) thin films with a NaCl-type structure have been prepared by reactive sputtering of chromium metal target in Ar/N 2 mixed gas. Nearly stoichiometric CrN thin films are obtained at the N2 mixing ratio of 20% and the total pressure of 0.67 Pa. Magnetic susceptibility, electrical resistivity and X-ray diffraction measurements indicate that these films show an antiferromagnetic first order phase transition at around 260 K. With the increase in N2 partial pressure, metastable over-stoichiometric CrN 1+x thin films are obtained. The compositions of samples prepared in pure N2 gas are almost CrN 1.2 and the lattice constant is 2% greater than that of the nearly-stoichiometric bulk CrN. Over-stoichiometric CrN 1+x thin films do not show the first order antiferromagnetic phase transition. Their X-T curves show a broad maximum at around 90 K. The electrical resistivity at room temperature decreases with increasing the nitrogen composition and the temperature coefficient of resistivity is always negative. The composition dependence of magnetic and electrical properties correlates to the variation in the density of state near the Fermi level detected by XPS.