Studies on control of spin ordering in magneto-dielectric thin films and their application for future electronics devices

磁电介质薄膜自旋有序控制及其在未来电子器件中的应用研究

基本信息

批准号：
17560621
负责人：
TOSHIYUKI Matsui
金额：
$ 2.3万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

The target of this research project is to synthesize room-temperature ferromagnetic dielectric thin films, which can possibly apply for novel magneto-dielectric devices. The followings are the main results obtained in the projects.(1)The single crystalline BaFe_<1-x>Zr_x0_<3-δ> (x=0.0-0.8) thin films were successfully produced on (001) SrTiO_3 substrates by pulsed laser-beam deposition. The films were found to be highly resistive, up to the leakage current density of about 1.1x10^<-5> A/cm^2 at the bias electric field of 150 kV/cm for the x=0.7 sample. This is much less than 10^<-4> of that for the BaFe0_<3-δ>, single crystalline film, which implies that the dielectric properties have been distinctly improved by zirconium substitution. The magnetization loop measured at 5 K for the x=0.7 sample clearly shows hysteresis as well as the presence of the remanent magnetization. Hence, the magnetic ordering for the x=0.7 sample has been greatly enhanced, possibly due to the ferromagnetic spi … More n alignment of Fe ions. It should be worthwhile mentioning that the x=0.7 sample still exhibits a ferromagnetic characteristic at room temperature. Consequently, BaFe_<0.3>Zr_<0.7>0_<3-δ> is a potential candidate for practical use in some magnetoelectric devices, such as a ferroelectric-ferromagnetic gate field-effect-transistor in the near future.(2)The single crystalline Ba(Co_<1-x>Mn_x)0_<3-δ> (x=0.2 and 0.7) films with the pseudo-cubic crystal structure were successfully synthesized. The films were found to be highly resistive with a dielectric constant of ε=5.2 at 5 K. In contrast, the films exhibited semiconductor-like conduction behavior at room temperature. Room temperature ferromagnetic ordering can be realized in samples with a saturation magnetization of 1.20 μB/fu for the x=0.2 sample, in contrast to 1.41 μB/fu for the x=0.7 sample. A possible origin of the observed magnetic ordering may be due to the superexchange coupling of Mn4+(d3)-O2--Co4+(d5) ions with a bonding angle of 180 degrees. Less

该研究项目的目标是合成室温铁磁旧膜，该薄膜可能适用于新型的磁性磁电器。以下是项目中获得的主要结果。（1）单晶BAFE_ <1-X> ZR_X0_ <3-udu>（X = 0.0-0.8）薄膜成功地在（001）SRTIO_3底物上通过脉冲激光束式底物成功产生。在X = 0.7样品的偏置电场上，薄膜被发现具有高度抵抗力，直至偏置电场的泄漏电流密度约为1.1x10^<-5> a/cm^2。对于BAFE0_ <3-δ>，单晶膜的少于10^<-4>，这意味着锆取代的饮食特性已明显改善。 X = 0.7样品在5 k下测得的磁化环清楚地显示出磁滞以及远期磁化的存在。因此，X = 0.7样品的磁顺序已大大增强，这可能是由于铁磁SPI…更多的Fe离子对齐。值得一提的是，X = 0.7样品在室温下仍表现出铁磁特征。因此，BAFE_ <0.3> Zr_ <0.7> 0_ <3-Δ>是在某些磁电器设备中实际使用的潜在候选者，例如在近期的铁电磁栅极磁场磁场效应 - 触觉 - 在不久的将来。伪立方体晶体结构成功合成。发现这些膜具有高度抗性，动态常数为ε= 5.2，在5 K处。相反，膜在室温下暴露了半导体样传导行为。室温铁磁有序可以在X = 0.2样品的饱和磁化的样品中实现，而X = 0.7样品的样品为1.41μb/fu。观察到的磁排序的可能起源可能是由于Mn4+（D3）-O2-CO4+（D5）离子的近极换耦合，其键合角度为180度。较少的