Magnetic properties of disordered ferrite and ilmenite-hematite thin films
Magnetic properties of disordered ferrite and ilmenite-hematite thin films
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DOI：
10.1016/j.jmmm.2008.11.069
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发表时间：
2009-04
影响因子：
2.7
通讯作者：
Katsuhisa Tanaka;K. Fujita;S. Nakashima;H. Hojo;T. Matoba
中科院分区：
文献类型：
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作者：
Katsuhisa Tanaka;K. Fujita;S. Nakashima;H. Hojo;T. Matoba
我们分别利用溅射和脉冲激光沉积方法制备了具有磁光和自旋电子学意义的无序铁酸锌（ZnFe_2O_4）和钛铁矿-赤铁矿（FeTiO_3-Fe_2O_3）固溶体薄膜，并研究了它们的磁、磁光和电学性质。ZnFe_2 O_4具有正常的尖晶石结构作为其稳定相，但部分Fe ~（3+）离子占据了组成溅射薄膜的ZnFe_2 O_4中的四面体和八面体位置。因此，沉积的薄膜即使在室温下也表现出大的磁化强度，尽管ZnFe 2 O 4的稳定相的磁相变温度低至10 K。此外，该薄膜在高达325 K的温度下表现出团簇自旋玻璃化转变。此外，ZnFe_2 O_4薄膜在400 nm左右的波长处表现出很大的法拉第效应。钛铁矿-赤铁矿固溶体是亚铁磁性半导体之一。大多数的组合物具有高于室温的居里温度，并且载体的类型只能通过改变组合物来调节。我们已经成功地合成了在具有（0001）面的蓝宝石衬底上外延生长的各种成分的固溶体薄膜，并且已经表明该薄膜是亚铁磁半导体。
We have synthesized thin films of disordered zinc ferrite (ZnFe2O4) and ilmenite–hematite (FeTiO3–Fe2O3) solid solution, the former and the latter of which are interesting from the viewpoints of magnetooptics and spintronics, respectively, by utilizing sputtering and pulsed laser deposition methods, and have explored their magnetic, magnetooptical, and electrical properties. Although ZnFe2O4possesses a normal spinel structure as its stable phase, some of the Fe3+ions occupy the tetrahedral as well as the octahedral sites in ZnFe2O4of which the sputtered thin film is composed. Consequently, the as-deposited thin film manifests large magnetization even at room temperature although the magnetic phase transition temperature of the stable phase of ZnFe2O4is as low as 10K. Also, the thin film exhibits a cluster spin glass transition at a temperature as high as 325K. Furthermore, the ZnFe2O4thin films exhibit large Faraday effects at a wavelength of 400nm or so. The ilmenite–hematite solid solution is one of the ferrimagnetic semiconductors. Most of the compositions possess Curie temperatures higher than room temperature, and the type of carrier can be tuned only by changing the composition. We have succeeded in synthesizing solid-solution thin films of various compositions grown epitaxially on sapphire substrates with a (0001) plane, and have shown that the thin films are ferrimagnetic semiconductors.