Fe-Co软磁薄膜物理特性的电场调制研究

Electric-Field Modulation of Physical Properties in Fe-Co Soft-Magnetic Thin Film

本文采用磁控溅射的方法在0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (简写为PMN-PT)上镀Fe3Co7合金薄膜,得到层状“Fe-Co/PMN-PT”薄膜。利用X射线衍射仪分析其结构,并通过扫描电镜显微镜观察材料的表面形貌,得到成相情况良好的样品。通过振动样品磁强计及磁电效应综合测试系统来测试薄膜的磁性及磁化性质,磁性测量表明Fe3Co7合金薄膜具有低矫顽力、高饱和磁化强度等特点,是一类很好的软磁材料;更重要的是,我们通过在PMN-PT层加不同强度的电场,研究Fe3Co7层的磁化性质。研究发现样品的饱和磁化强度和矫顽力均随着电场的变化而变化,当外加电场E = 1 kV/cm时,饱和磁化强度的变化率ΔM/ME=0达到7.3%。这一结果表明外加电场对Fe3Co7/PMN-PT复合材料的磁性有明显的调制作用,即Fe-Co/PMN-PT复合材料中存在电场调控磁性特征。这一结果为磁化强度的调制增加了调控自由度,在多态存储器、电场探测等领域具有潜在的应用。

In this paper, Fe3Co7 film is successfully deposited on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (named as PMN-PT) by magnetron sputtering technology. After fabricated “Fe3Co7/PMN-PT” laminated composite, the structure of the thin film is characterized by x-ray diffraction. The surface and interface shapes of the FeCo/PMN-PT thin film are measured by scanning electron microscopy (SEM). The results indicate that there is no diffusion between Fe-Co phase and PMN-PT phase. The measurements of the magnetic properties for the Fe-Co film are carried out by vibrating sample magnetometer (VSM) and magnetoelectric effect test systems. The results reveal that the Fe3Co7 film is an important soft magnetic material with low coercivity and high saturation magnetization. Furthermore, the magnetic properties of the Fe3Co7/PMN-PT thin film are well investigated when applying different dc electric fields on PMN-PT layer. The results indicate that both the saturation magnetization and coercivity of the films change with electric field varying. When E = 1 kV/cm, ΔM/ME=0 up to 7.3% is obtained, which means the applying electric field has obvious effect on the magnetic of the Fe3Co7/PMN-PT laminated composite. The results provide another modulation degree of freedom for the magnetization, which may have potential application in multi-state memory, electric field detector, etc.