Spin dynamics and spin freezing at ferromagnetic quantum phase transitions

铁磁量子相变的自旋动力学和自旋冻结

• 批准号: 48595040
• 负责人: Professor Dr. Christian Pfleiderer
• 金额: --
• 依托单位: Arbeitsgruppe Neutronenstreuung
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/48595040?language=en
• 关键词: Spin; dynamics; spin; freezing; ferromagnetic

An increasing number of experimental and theoretical studies suggest that quantum criticality of itinerant-electron ferromagnets, quite generally, does not exist in real materials. This raises the question what mechanisms pre-empt ferromagnetic quantum criticality. In the simplest scenario the single-particle density of states or certain many body interactions drive the quantum phase transition first order. Further possibilities include the emergence of ordered phases such as superconductivity or partial electronic order, e.g., nematic electronic phases. Finally, the emergence of long-range modulations and electronic phase separations may be expected that are driven by weak residual interactions. We propose to search for electronic phase separations near ferromagnetic quantum criticality in a wide range of transition metal and rare earth compounds using neutron depolarization radiography and neutron depolarization tomography; these are new neutron scattering techniques we developed during the first funding period. Our studies will be complemented by conventional inelastic neutron scattering studies and comprehensive measurements of the bulk properties.

越来越多的实验和理论研究表明，在真实的材料中，巡游电子铁磁体一般不存在量子临界性。这就提出了一个问题，即什么机制可以预先取代铁磁量子临界性。在最简单的情况下，单粒子态密度或某些多体相互作用驱动一阶量子相变。进一步的可能性包括有序相的出现，例如超导性或部分电子有序，电子阶段。最后，长程调制和电子相分离的出现可能是由弱剩余相互作用驱动的。我们建议使用中子去极化射线照相术和中子去极化层析成像术在广泛的过渡金属和稀土化合物中寻找铁磁量子临界附近的电子相分离;这些是我们在第一个资助期内开发的新中子散射技术。我们的研究将补充传统的非弹性中子散射研究和全面测量的散装性能。

项目成果

Critical spin-flip scattering at the helimagnetic transition of MnSi

• DOI: 10.1103/physrevb.89.180408
• 发表时间: 2014-03
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: J. Kindervater;W. Haussler;M. Janoschek;C. Pfleiderer;P. Boni;M. Garst

Emergent electrodynamics of skyrmions in a chiral magnet

• DOI: 10.1038/nphys2231
• 发表时间: 2012-04-01
• 期刊: NATURE PHYSICS
• 影响因子: 19.6
• 作者: Schulz, T.;Ritz, R.;Rosch, A.
• 通讯作者: Rosch, A.

Vibrating-coil magnetometry of the spin liquid properties of Tb2Ti2O7.

• DOI: 10.1103/physrevlett.109.047201
• 发表时间: 2012-06
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: S. Legl;C. Krey;S. Dunsiger;H. Da̧bkowska;J. Rodriguez;G. Luke;C. Pfleiderer

Parasitic small-moment antiferromagnetism and nonlinear coupling of hidden order and antiferromagnetism in URu2Si2 observed by Larmor diffraction.

• DOI: 10.1103/physrevlett.104.106406
• 发表时间: 2009-09
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: P. G. Niklowitz;P. G. Niklowitz;C. Pfleiderer;Thomas Keller;Thomas Keller;Matthias Vojta;Yingkai Huang;J. Mydosh

Ferrimagnetism in Fe-rich NbFe 2

富铁 NbFe 2 中的亚铁磁性

• DOI: 10.1103/physrevb.85.115137
• 发表时间: 2012
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Haynes T