Ferromagnetism in chemically reduced LiNbO3 and LiTaO3 crystals
Ferromagnetism in chemically reduced LiNbO3 and LiTaO3 crystals
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DOI：
10.1088/0022-3727/49/19/195005
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
Tao Yan;N. Ye;Liuwei Xu;Y. Sang;Yanxue Chen;Wei Song;X. Long;Ji-yang Wang;Hong Liu
中科院分区：
文献类型：
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作者：
Tao Yan;N. Ye;Liuwei Xu;Y. Sang;Yanxue Chen;Wei Song;X. Long;Ji-yang Wang;Hong Liu
本工作首次研究了室温下块状 LiNbO3 和 LiTaO3 的铁磁性。化学计量的LiNbO3 是非磁性的，而同质的LiNbO3 和LiTaO3 显示出非常弱的铁磁性。在流动氮气下对锌和碳酸锂粉末的混合物进行化学还原后，每个样品的铁磁行为变得清晰，磁化强度值增加。还原同成分LiNbO3的饱和磁化强度、剩磁和矫顽场分别为7.0×10−3 emu g−1、0.65×10−3 emu g−1和0.050 kOe。化学还原的LiNbO3和LiTaO3的铁磁性可以通过考虑固有的Li空位、表面上净自旋非零的Nb4+（或Ta4+）的出现以及表面的氧空位来解释。
The ferromagnetism of bulk LiNbO3 and LiTaO3 at room temperature was investigated for the first time in the present work. The stoichiometric LiNbO3 is non-magnetic, while congruent LiNbO3 and LiTaO3 show very weak ferromagnetism. After chemical reduction in a mixture of zinc and lithium carbonate powders under flowing nitrogen, the ferromagnetic behavior of each sample became clear, with an increased value of magnetization. The saturation magnetization, the magnetic remanence and the coercive field of reduced congruent LiNbO3 are 7.0 × 10−3 emu g−1, 0.65 × 10−3 emu g−1 and 0.050 kOe, respectively. The ferromagnetism of chemically reduced LiNbO3 and LiTaO3 can be explained by considering the intrinsic Li vacancies, the appearance of Nb4+ (or Ta4+) on the surface with non-zero net spin and the oxygen vacancies at the surface.