Magnetoresistance of coherently strained La2/3Ba1/3MnO3/SrTiO3 superlattices
Magnetoresistance of coherently strained La2/3Ba1/3MnO3/SrTiO3 superlattices
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DOI：
10.1103/physrevb.62.15806
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发表时间：
2000-12-15
影响因子：
3.7
通讯作者：
Gross, R
中科院分区：
文献类型：
--
作者：
Lu, YF;Klein, J;Gross, R
用激光分子束外延技术在（100）SrTiO_3和（100）NdGa_3衬底上制备了一系列SrTiO_3/La_2/3Ba_（1/3）MnO_3相干应变多层薄膜。通过面内相干应变，可以通过改变SrTiO 3和La 2/3Ba 1/3 MnO 3层的相对厚度来连续地将面外晶格常数从3.916调整到3.975埃。该应变导致La 2/3Ba 1/3 MnO 3的双轴形变ε（bi），其强烈影响电输运性质和磁阻。我们的测量结果表明，有一个明确的相关性之间的电阻率（bi）和温度T-p对应的最大值在电阻率-温度曲线以及测量的磁阻。通过改变应变，我们可以推导出量Delta =（T-p/T-p（体））（d（2）T（p）/d ε（2）（bi）），给出材料性质对双轴应变的敏感性。我们的数据提供了证据的Jahn-Teller电子-声子耦合的掺杂锰氧化物的相关性。我们的分析进一步表明，双轴应变是一个重要的变量，必须考虑到用于基于掺杂锰氧化物的磁电子器件的薄膜结构的设计。
A series of coherently strained multilayer thin films of SrTiO3/La2/3Ba1/3MnO3 have been fabricated on (100) SrTiO3 and (100) NdGaO3 substrates by laser molecular-beam epitaxy. By the in-plane coherency strain the out-of-plane lattice constant could be continuously adjusted from 3.916 to 3.975 Angstrom by varying the relative thickness of the SrTiO3 and La2/3Ba1/3MnO3 layers. The strain results in a biaxial distortion epsilon (bi) of La2/3Ba1/3MnO3 that strongly affects the electrical transport properties and the magnetoresistance. Our measurements show that there is a clear correlation between epsilon (bi) and the temperature T-p corresponding to the maximum in the resistivity versus temperature curves as well as the measured magnetoresistance. By varying the strain we could derive the quantity Delta = (T-p/T-p(bulk))(d(2)T(p)/d epsilon (2)(bi)) giving the sensitivity of the materials properties to biaxial strain. Our data provide evidence for the relevance of the Jahn-Teller electron-phonon coupling in the doped manganites. Our analysis further shows that biaxial strain is an important variable that has to be taken into account in the design of thin-film structures used for magnetoelectronic devices based on doped manganites.