High-Temperature Magnetic Insulating Phase in Ultrathin La0.67Sr0.33MnO3 Films
High-Temperature Magnetic Insulating Phase in Ultrathin La0.67Sr0.33MnO3 Films
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DOI：
10.1103/physrevlett.109.157207
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发表时间：
2012-10-12
影响因子：
8.6
通讯作者：
Rijnders, Guus
中科院分区：
文献类型：
--
作者：
Boschker, Hans;Kautz, Jaap;Rijnders, Guus
我们研究了在 SrTiO3 (110) 基底上生长的超薄 La0.67Sr0.33MnO3 薄膜的磁性和电导率的厚度依赖性。我们发现了 10 个晶胞的临界厚度，低于该厚度薄膜的导电性消失，同时居里温度升高，表明在室温下存在磁绝缘相。这些样品的居里温度约为 560 K，饱和磁化强度为 1.2 +/- 0.2 mu(B)/Mn。 n < 10 的超薄膜中的倾斜反铁磁绝缘相与具有不同氧八面体旋转模式的更高对称性结构相的出现相一致。这种应变工程相是室温自旋极化隧道器件中绝缘隧道势垒的有趣候选者。
We present a study of the thickness dependence of magnetism and electrical conductivity in ultrathin La0.67Sr0.33MnO3 films grown on SrTiO3 (110) substrates. We found a critical thickness of 10 unit cells below which the conductivity of the films disappeared and simultaneously the Curie temperature increased, indicating a magnetic insulating phase at room temperature. These samples have a Curie temperature of about 560 K with a significant saturation magnetization of 1.2 +/- 0.2 mu(B)/Mn. The canted antiferromagnetic insulating phase in ultra thin films of n < 10 coincides with the occurrence of a higher symmetry structural phase with a different oxygen octahedra rotation pattern. Such a strain engineered phase is an interesting candidate for an insulating tunneling barrier in room temperature spin polarized tunneling devices.