射频溅射Fe1-xNix/Cu超晶格的结构与磁性

Structure and Magnetic Properties of RF Sputtered Fe1-xNix/Cu Superlattices

  • 摘要: 应用射频溅射技术制备了面心立方结构的Fe1-xNix/Cu(x=0.26~0.54)金属超晶格.Mgo单晶衬底的采用以及在面心立方结构的Cu上实施外延等措施保证了在Ni质量分数低至0.26时Fe-Ni合金层仍保持了良好的面心立方的晶体结构,而且直到液氦温区这种面心立方结构仍是稳定的.磁性测量表明,当Fe-Ni合金层的Ni质量分数低至接近因瓦合金成分(x=0.35)时,其饱含磁矩呈下降趋势,即表现出偏离Slater-Pauling规律的倾向.同时,面心立方结构的Fe-Ni合金层的饱合磁矩有很强的温度依赖性,表明面心立方结构的Fe-Ni合金中饱含磁矩对Slater-Pauling规律的偏离与所谓的马氏体预相变无关,而与合金中Fe-Fe原子对的反铁磁性耦合有关.

     

    Abstract: Applying ny sputtering techniques, a series of fcc (Fe1-xNix/Cu)10 superlattices are prepared with Ni concentrations x ranging from 0.26 to 0.54. The use of MgO single crystal substrates and Cu sublayers in the superlattice growth ensure well defined fcc crystal structures in the Fe-Ni sublayers with a Ni concentration as low as 26% and down to liquid helium temperatures.The magnetization of the Fe-Ni sublayers in the super-lattices is reduced when the composition of the Fe-Ni layers approaches the Invar composition, i.e., it shows a deviation from the well-known Slater-Pauling curve. Strong dependence of magnetization on temperature is also observed for the Fe-Ni sublayers with Invar compositions, consistent with the behavior of the bulk Fe-Ni Invar alloys. It is concluded that the deviation of magnetic moment of FeNi alloys near the Invar composition may not be attributed to the so-called premartensitic transformation, but to the Fe-Fe antiferromagnetic interactions in the alloys.

     

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