In situ magnetometry studies of magnetoelectric LSMO/PZT heterostructures
In situ magnetometry studies of magnetoelectric LSMO/PZT heterostructures
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DOI：
10.1103/physrevb.87.094416
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发表时间：
2013-03-14
影响因子：
3.7
通讯作者：
Hahn, Horst
中科院分区：
文献类型：
--
作者：
Leufke, Philipp M.;Kruk, Robert;Hahn, Horst
为了确定和量化铁磁/铁电界面的磁电耦合特性，采用大距离磁控溅射法制备了La 1-xSrxMnO 3/Pb（Zr，Ti）O3（LSMO/PZT）异质结构。在这种薄膜中实现的显著高的横向均匀性允许铁电器件面积超过6 mm（2）。这使得超导量子干涉仪（SQUID）的磁响应的测量系统，完全原位，变化的反射铁电极化。充电时的磁调制的温度依赖性和对铁电刺激的磁响应表明场效应主导的耦合机制，并且通常确认LSMO的静电空穴（h（+））掺杂的概念。的调制磁化进行了全面的分析，在很宽的范围内的静电感应表面电荷浓度。对于低温下的小电荷调制，线性调谐系数约为-3.6 μ（B）/h（+）。这表明反铁磁耦合的激活，即使是非常小的表面电荷密度。同时，在较高的表面电荷浓度的磁转变温度的移位表明在LSMO/PZT界面处的铁磁相的存在。最后，磁电耦合的物理图像中，提出这些定量的结果是一致的解释，在表面电荷依赖的电子相分离的铁磁/铁电界面处的反铁磁和铁磁区域的共存。DOI：10.1103/PhysRevB.87.094416
In order to identify and quantify characteristics of the magnetoelectric coupling at ferromagnetic/ferroelectric interfaces, epitaxial La1-xSrxMnO3/Pb(Zr,Ti)O-3 (LSMO/PZT) heterostructures were deposited by large-distance magnetron sputtering. The remarkably high lateral uniformity achieved in such films allowed for a ferroelectric device area of more than 6 mm(2). This has enabled for superconductive quantum interference device (SQUID) measurements of the magnetic response to the systematically, completely in situ, varied remanent ferroelectric polarization. Temperature dependence of the magnetic modulation upon charging and the magnetic response to the ferroelectric stimulation indicate a field-effect dominated coupling mechanism and generally confirm the concept of electrostatic hole (h(+)) doping of LSMO. The modulation of magnetization was comprehensively analyzed for a broad range of electrostatically induced surface charge concentrations. For small charge modulations at low temperature a linear tuning coefficient of approximate to -3.6 mu(B)/h(+) has been determined. This suggests the activation of an antiferromagnetic coupling, even for very small surface charge densities. Simultaneously, a shift in the magnetic transition temperature at higher surface charge concentration indicates the presence of a ferromagnetic phase at the LSMO/PZT interface. Eventually, a physical picture of magnetoelectric coupling is proposed in which these quantitative results are consistently interpreted, in terms of a surface-charge dependent electronic phase separation with the coexistence of antiferromagnetic and ferromagnetic regions at the ferromagnetic/ferroelectric interface. DOI: 10.1103/PhysRevB.87.094416