Exchange Bias Effect and Magnetic Properties in La0.7Sr0.3MnO3-NiO Nanocomposite Films
Exchange Bias Effect and Magnetic Properties in La0.7Sr0.3MnO3-NiO Nanocomposite Films
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La0.7Sr0.3MnO3-NiO纳米复合薄膜的交换偏压效应及磁性能
DOI：
10.1109/tmag.2013.2279569
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发表时间：
2014-01-01
影响因子：
2.1
通讯作者：
Zhang, Zhidong
中科院分区：
文献类型：
--
作者：
Ning, Xingkun;Wang, Zhan Jie;Zhang, Zhidong
研究了脉冲激光沉积La0.7Sr0.3MnO(LSMO)-NiO纳米复合薄膜在(001)和(110)单晶衬底上的磁交换耦合效应。与相同厚度的纯LSMO薄膜相比，薄膜的矫顽场H-C=560Oe。在4000 Oe的场冷条件下，复合薄膜表现出较大的交换偏置场H-E=140 Oe。交换偏置场随温度升高而减小，在约45K时变为零，这相当于传统的交换偏置阻断温度(T-B)，与(001)或(110)SrTiO3衬底上的外延生长方向无关。我们推测，在NiO和LSMO界面上可能存在磁相互作用，或者Ni和Mn离子之间存在电荷转移，从而在界面上形成铁磁相互作用。居里温度T-C由LSMO单膜的340K降至纳米复合膜的200K。结果表明，复合膜的磁态与Mn-O-Mn和Mn-O-Ni自旋作用能直接相关。此外，晶界处的Mn-O-Ni还可能形成钉扎铁磁性LSMO相的磁性区。
The magnetic exchange coupling effect has been investigated in La0.7Sr0.3MnO3 (LSMO)-NiO nanocomposite films prepared by pulsed laser deposition on SrTiO3 (001) and (110) single crystal substrates. The films show an enhanced coercivity field H-C = 560 Oe compared with the same thickness single pure LSMO thin film. The composite films exhibit a large exchange bias field H-E = 140 Oe after applying a 4000 Oe field cooling. The values of the exchange bias field decrease with increasing temperature and become zero at about 45 K, which corresponds to the conventional exchange bias blocking temperature (T-B), regardless of epitaxial growth directions on (001) or (110) SrTiO3 substrates. We speculate that there may be magnetic interaction at the NiO and LSMO boundaries or charge transfer between the Ni and Mn ions, resulting in the formation of ferromagnetic interaction at the interface. The Curie temperature T-C decreased from 340 K of the LSMO single film to 200 K of the nanocomposite film. The results demonstrate that the magnetic state of the composite film is directly related to the Mn-O-Mn and Mn-O-Ni spin interaction energy. In addition to this, the Mn-O-Ni at the boundary may also form the magnetic region that pins the ferromagnetic LSMO phase.