Mixed ferromagnetic/antiferromagnetic hybrid phase in stripe and bubble domain structures for magnonic crystal and race track applications

用于磁振晶体和赛道应用的条带和气泡域结构中的混合铁磁/反铁磁杂化相

• 批准号: 514946929
• 负责人: Professor Dr. Olav Hellwig
• 金额: --
• 依托单位: Faculty of Physics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/514946929?language=en
• 关键词: Mixed; ferromagnetic; antiferromagnetic; hybrid; phase

In this project we want to study a new perpendicular magnetic anisotropy (PMA) hybrid structure consisting of periodic ferromagnetic (FM) out-of-plane (oop) up and down stripe or bubble domains separated by antiferromagnetic (AFM) in-plane (ip) Bloch-type or mixed Bloch-Neel-type domain walls. We are using a double multilayer magnetic thin film platform [1] to control precisely the various involved magnetic energy contributions in order to stabilize this new mixed FM/AFM hybrid phase. Targeting an energy balance characterized by strong PMA with simultaneously large demagnetization fields, thus promoting highly periodic stripe domain patterns [1-3], we add to this energy setting a comparably weak AFM interlayer exchange coupling (IEC). For this so far unexplored magnetic energy constellation we expect that the weak AFM-IEC only reveals itself within the ip domain walls, as inside the oop stripe domains itself the AFM-IEC is overcome by the strong demagnetization fields perpendicular to the film plane. After investigating the exact structure of this new phase by experimental techniques (magnetometry, magnetic force microscopy and Lorentz transmission electron microscopy) as well as micromagnetic simulations, we will perform a detailed study of the static properties and field reversal behavior of this new FM/AFM hybrid phase. As part of this investigation, we will also determine the stability region of the phase within the complex energy landscape consisting of PMA, demagnetization and AFM-IEC energy at remanence as well as in combination with externally applied magnetic fields. In particular, we will explore the stabilization of highly-periodic parallel stripe and quasi-hexagonal bubble domain patterns at remanence by previously exposing the system to specific magnetic field protocols [3]. Finally, we want to focus on two possible applications for this new FM/AFM hybrid structure: 1) magnetic race track memory type systems based on magnetic bubble propagation via electric current pulses along a lithographically or otherwise confined magnetic strip line [4,5] using Hall effect analysis and magnetic force microscopy 2) fabrication and optimization of reprogrammable self-organized magnonic crystal structures based on highly-periodic parallel stripe domain patterns [6,7]. [1] O. Hellwig et al., J. Mag. Mag. Mat. 319, 13 (2007). [2] O. Hellwig et al., Physica B: Condensed Matter 336, 136 (2003). [3] L. Fallarino et al., Phys. Rev. B 99, 024431 (2019). [4] S. S. P. Parkin et al., Science 320, 190 (2008). [5] R. Tomasello et al., Scientific Reports 4, 6784 (2014). [6] C. Banerjee et al., Phys. Rev. B 96, 024421 (2017). [7] P. Gruszecki et al., Book chapter in “SSP-70 - RECENT ADVANCES IN TOPOLOGICAL FERROICS AND THEIR DYNAMICS and in Solid State Physics, Volume 70 (2019).

在这个项目中，我们想研究一种新的垂直磁各向异性（PMA）混合结构，由周期性铁磁（FM）面外（oop）的向上和向下的条纹或气泡畴由反铁磁（AFM）面内（ip）布洛赫型或混合布洛赫-尼尔型畴壁分离。我们使用双层多层磁性薄膜平台[1]来精确控制各种相关的磁能贡献，以稳定这种新的混合FM/AFM混合相。目标是以强PMA为特征的能量平衡，同时具有大的退磁场，从而促进高度周期性的条纹畴图案[1-3]，我们向该能量设置中添加了弱AFM层间交换耦合（IEC）。对于这个迄今为止尚未探索的磁能星座，我们预计弱AFM-IEC仅在ip畴壁内显现出来，因为在oop条纹畴本身内部，AFM-IEC被垂直于薄膜平面的强退磁场克服。在通过实验技术（磁力测量，磁力显微镜和洛伦兹透射电子显微镜）以及微磁学模拟研究了这种新相的确切结构之后，我们将对这种新的FM/AFM混合相的静态特性和场反转行为进行详细的研究。作为这项调查的一部分，我们还将确定的相位内的复杂的能量景观，包括PMA，退磁和AFM-IEC能量在剩磁以及在外部施加的磁场相结合的稳定区域。特别是，我们将通过预先将系统暴露于特定的磁场协议来探索高周期性平行条纹和准六边形气泡畴图案在剩磁下的稳定性[3]。最后，我们想关注这种新的FM/AFM混合结构的两种可能的应用：1）基于磁泡经由电流脉冲沿光刻或其它方式限制的磁条线沿着传播的磁跑道存储器型系统[4，5]使用霍尔效应分析和磁力显微镜2）基于高度可编程的自组织磁振子晶体结构的制造和优化，周期性平行条纹畴模式[6，7]。[1]O. Hellwig等人，J. Mag. Mag. Mat. 319，13（2007）。[2]O. Hellwig等人，Physica B：Condensed Matter 336，136（2003）. [3]L. Fallarino等人，物理修订版B 99，024431（2019）。[4]S. S. P. Parkin等人，Science 320，190（2008）。[5]R. Tomasello等人，科学报告4，6784（2014）。[6]C. Banerjee等人，物理修订版B 96，024421（2017）。[7]P. Gruszecki等人，书章“SSP-70 -最近的进展在拓扑铁及其材料和固态物理，第70卷（2019年）。