Unconventional ferromagnetism in epitaxial (111) LaNiO3
Unconventional ferromagnetism in epitaxial (111) LaNiO3
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DOI：
10.1103/physrevb.98.121105
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发表时间：
2018-09
影响因子：
3.7
通讯作者：
T. Asaba;Z. Xiang;T. H. Kim;M. Rzchowski;C. Eom;Lu Li
中科院分区：
文献类型：
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作者：
T. Asaba;Z. Xiang;T. H. Kim;M. Rzchowski;C. Eom;Lu Li
本文报道了在非磁性绝缘衬底${\mathrm{LaAlO}}_{3}$（111）衬底上生长的顺磁性金属${\mathrm{LaNiO}}_{3}$薄膜的铁磁性。薄膜在磁阻上表现出较大的磁滞回线、反常霍尔效应和六倍的各向异性磁阻。结合在同一体系中报道的铁电性和反转对称性破缺，这些结果表明，在衬底的几何约束下，顺磁性金属可以转变为铁磁性半导体。铁磁基态与自旋轨道耦合相关金属的预测自旋分裂费米表面一致。此外，我们的研究结果表明，线性磁电阻为正，磁滞回线的符号反转，这与理论预测的大质量狄拉克点的存在一致。
We report the observation of ferromagnetism in thin films of paramagnetic metal ${\mathrm{LaNiO}}_{3}$ grown on nonmagnetic insulating substrate ${\mathrm{LaAlO}}_{3}$(111) substrates. The films exhibit a large hysteresis loop on magnetoresistance and anomalous Hall effect as well as sixfold anisotropic magnetoresistance. Together with the ferroelectricity and inversion symmetry breaking reported in the same system, these results suggest that, by the geometric constraints by the substrate, paramagnetic metals can turn into ferromagnetic semiconductors. The ferromagnetic ground state is consistent with the predicted spin-split Fermi surfaces of spin-orbit-coupled correlated metals. Moreover, our results reveal a positive linear magnetoresistance and a sign reversal of hysteresis loop, which is consistent with the existence of a massive Dirac point as predicted by theories.