Addressing Current Issues in Multiferroics

解决多铁性的当前问题

• 批准号: EP/J017191/1
• 负责人: J M Gregg
• 金额: $ 44.99万
• 依托单位: Queen's University Belfast
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ017191%2F1
• 关键词: Addressing; Current; Issues; Multiferroics

The smooth operation of the modern world depends on our ability to store and access data reliably. Almost everything we need, from the accurate management of bank accounts to the flexibility of digital entertainment, requires the reading and interpretation of strings of binary '1's or '0's. At the heart of data storage, such binary numbers usually exist in the form of either the polarity of electrical charge (in DRAM, Flash or FRAM) or the orientation of magnetisation (in magnetic hard-drives). Charge-storage devices and magnetic storage devices both have negative aspects about their architectures or operation, and so for some years there has been interest in developing a memory element that combines the positive features of each, allowing 'writing' of information to be done electrically, and 'reading' to be done magnetically. Materials that are both ferromagnetic and ferroelectric would be highly desirable for such applications and, as a result, so-called 'multiferroics' have become a topic of great recent research interest. Unfortunately, there are very few known multiferroic systems and none has been discovered to date which can readily be made and simultaneously displays both large polarisation and magnetisation. The first element of this proposal is therefore to explore two relatively new groups of multiferroics (birelaxors and lattice strained EuTiO3) to see if they can offer properties that are superior to the best known multiferroic currently available (bismuth ferrite). The use of a multiferroic in a memory element requires the manipulation of magnetic and ferroelectric regions, known as domains. While a great deal is known about domain behaviour in ferromagnets and in ferroelectrics separately, much less is known about the static and dynamic behaviour of multiferroic domains. Exploration of domains in meso and nanoscale objects (dimensions relevant to high density memory) will be performed on small scale single crystals, cut from high purity bulk material using a Focused Ion Beam-based methodology uniquely developed by the applicants. To date this has given extremely clear information on ferroelectrics and should be ideal for fundamental investigations into multiferroic domain properties.In addition to interest in multiferroic memory, researchers have become increasingly excited by the potential use of multiferroics in more exotic applications - the domain walls in bismuth ferrite have been found to act as planar conductors and large photovoltaic effects have been displayed. To date, such effects have only been probed in thin films grown by pulsed laser deposition. While this is a useful and flexible growth technique it has a tendency to introduce significant levels of defects that can lead to properties which are extrinsic, rather than intrinsic to the material. We wish to examine the properties of single crystal thin films of bismuth ferrite (and later birelaxors) made using the established Focused Ion Beam process mentioned above for such exotic domain wall and photovoltaic effects. Importantly, using this approach should allow a different view, which may corroborate or conflict with information to date only obtained through PLD grown films.

现代世界的平稳运行取决于我们可靠地存储和访问数据的能力。我们所需要的几乎所有东西，从银行账户的精确管理到数字娱乐的灵活性，都需要对二进制“1”或“0”的字符串进行阅读和解释。在数据存储的核心，这样的二进制数通常以电荷的极性（在DRAM、闪存或弗拉姆中）或磁化方向（在磁性硬盘驱动器中）的形式存在。电荷存储设备和磁存储设备都具有关于它们的架构或操作的负面方面，并且因此多年来一直有兴趣开发一种存储器元件，该存储器元件结合了每一种的正面特征，允许以电的方式完成信息的“写入”，并且以磁的方式完成“阅读”。铁磁性和铁电性的材料对于这样的应用是非常理想的，因此，所谓的“多铁性”已经成为最近研究兴趣的主题。不幸的是，已知的多铁性系统很少，迄今为止还没有发现可以容易地制造并同时显示大极化和磁化的系统。因此，该提案的第一个要素是探索两个相对较新的多铁性组（双弛豫和晶格应变EuTiO 3），看看它们是否可以提供比目前最知名的多铁性（铁酸铋）更上级的性能。在存储器元件中使用多铁性需要操纵被称为畴的磁性和铁电区域。虽然我们对铁磁体和铁电体中的畴行为分别有了很多了解，但对多铁性畴的静态和动态行为却知之甚少。在介观和纳米级物体（与高密度存储器相关的尺寸）中的域的探索将在小尺度单晶上进行，所述小尺度单晶使用由申请人独特开发的基于聚焦离子束的方法从高纯度块体材料切割。到目前为止，这已经给出了非常清晰的铁电体的信息，应该是理想的多铁性域properties.除了在多铁性存储器的兴趣的基础研究，研究人员越来越兴奋的潜在用途的多铁性在更奇特的应用-铋铁氧体的畴壁已被发现作为平面导体和大的光伏效应已被显示。到目前为止，这种影响只在脉冲激光沉积生长的薄膜中被探测到。虽然这是一种有用且灵活的生长技术，但它倾向于引入显著水平的缺陷，这些缺陷可能导致材料的外在性质，而不是材料的内在性质。我们希望研究使用上述已建立的聚焦离子束工艺制造的铁酸铋（以及后来的双弛豫体）单晶薄膜的特性，以获得这种奇异的畴壁和光伏效应。重要的是，使用这种方法应该允许不同的观点，这可能与迄今为止仅通过PLD生长的膜获得的信息相证实或冲突。

项目成果

Magnetic switching of ferroelectric domains at room temperature in multiferroic PZTFT.

• DOI: 10.1038/ncomms2548
• 发表时间: 2013
• 期刊: Nature communications
• 影响因子: 16.6

Injection and controlled motion of conducting domain walls in improper ferroelectric Cu-Cl boracite.

• DOI: 10.1038/ncomms15105
• 发表时间: 2017-05-16
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: McQuaid RGP;Campbell MP;Whatmore RW;Kumar A;Gregg JM
• 通讯作者: Gregg JM

Exploring the Magnetoelectric Coupling at the Composite Interfaces of FE/FM/FE Heterostructures.

• DOI: 10.1038/s41598-018-35648-1
• 发表时间: 2018-11-26
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Pradhan DK;Kumari S;Vasudevan RK;Strelcov E;Puli VS;Pradhan DK;Kumar A;Gregg JM;Pradhan AK;Kalinin SV;Katiyar RS
• 通讯作者: Katiyar RS

Hall effect in charged conducting ferroelectric domain walls.

• DOI: 10.1038/ncomms13764
• 发表时间: 2016-12-12
• 期刊: Nature communications
• 影响因子: 16.6

A Local Superlens

• DOI: 10.1021/acsphotonics.5b00365
• 发表时间: 2016-01
• 期刊: ACS Photonics
• 影响因子: 7
• 作者: S. C. Kehr;R. G. McQuaid;L. Ortmann;T. Kämpfe;F. Kuschewski;D. Lang;J. Doering;J. Gregg;L. Eng