螺旋磁性

螺旋磁性是一种相邻磁矩的自旋以螺旋模式进行排列的磁序形式，其特征转角介于0到180度之间。这种现象是铁磁和反铁磁交换相互作用之间竞争的结果，也可以分别将铁磁和反铁磁视为具有0度和180度特征转角的螺旋磁结构。螺旋磁序本质上可以是左旋或右旋的，因此螺旋磁序破坏了空间反演对称性。 严格来说，螺旋磁体并没有永久磁矩，因此有时被认为是一种复杂的反铁磁体。而锥形磁性除了具有螺旋调制外还有永久磁矩（例如，金属钬在低于20K时表现出锥形磁性）。是否具有永久磁矩可以将螺旋磁体与锥形磁体区分开来。 螺旋磁性的概念于1959年首次提出，它可以作为对二氧化锰磁结构的解释。螺旋磁性最初应用于中子衍射，后来发现它可以被洛伦兹电子显微镜更直接地观察到。据报道，大部分材料在低温下表现出螺旋磁性，然而也有一些螺旋磁结构可以在室温下保持稳定。许多螺旋磁体具有手性立方结构，例如B20晶体结构类型。 就像普通铁磁体具有分隔各个磁畴的畴壁一样，螺旋磁体也有自己的以拓扑电荷为特征的畴壁。 反对称交换 Perreault, Christopher S.; Vohra, Yogesh K.; dos Santos, Antonio M.; Molaison, Jamie J. Neutron diffraction study of magnetic ordering in high pressure phases of rare earth metal holmium. Journal of Magnetism and Magnetic Materials (Elsevier BV). 2020, 507: 166843. Bibcode:2020JMMM..50766843P. OSTI 1607351. doi:10.1016/j.jmmm.2020.166843.  Yoshimori, Akio. A New Type of Antiferromagnetic Structure in the Rutile Type Crystal. Journal of the Physical Society of Japan (Physical Society of Japan). 1959, 14 (6): 807–821. Bibcode:1959JPSJ...14..807Y. doi:10.1143/jpsj.14.807.  Uchida, Masaya; Onose, Yoshinori; Matsui, Yoshio; Tokura, Yoshinori. Real-Space Observation of Helical Spin Order. Science (American Association for the Advancement of Science (AAAS)). 2006, 311 (5759): 359–361. Bibcode:2006Sci...311..359U. PMID 16424334. doi:10.1126/science.1120639.  Zhang, S. L.; Stasinopoulos, I.; Lancaster, T.; Xiao, F.; Bauer, A.; et al. Room-temperature helimagnetism in FeGe thin films. Scientific Reports (Springer Science and Business Media LLC). 2017, 7 (1): 123. Bibcode:2017NatSR...7..123Z. PMC 5427977 . PMID 28273923. doi:10.1038/s41598-017-00201-z .  Schoenherr, P.; Müller, J.; Köhler, L.; Rosch, A.; Kanazawa, N.; Tokura, Y.; Garst, M.; Meier, D. Topological domain walls in helimagnets. Nature Physics (Springer Science and Business Media LLC). 2018, 14 (5): 465–468. Bibcode:2018NatPh..14..465S. arXiv:1704.06288 . doi:10.1038/s41567-018-0056-5.  Regulski, M.; Przeniosło, R.; Sosnowska, I.; Hoffmann, J.-U. Incommensurate magnetic structure of β−MnO2. Physical Review B (American Physical Society (APS)). 2003-11-03, 68 (17): 172401. ISSN 0163-1829. doi:10.1103/physrevb.68.172401.  Martin, N.; Mirebeau, I.; Franz, C.; Chaboussant, G.; Fomicheva, L. N.; Tsvyashchenko, A. V. Partial ordering and phase elasticity in the MnGe short-period helimagnet (PDF). Physical Review B (American Physical Society (APS)). 2019-03-13, 99 (10): 100402(R) [2021-09-26]. Bibcode:2019PhRvB..99j0402M. ISSN 2469-9950. doi:10.1103/physrevb.99.100402. （原始内容存档 (PDF)于2021-12-30）.  Stishov, Sergei M; Petrova, A E. Itinerant helimagnet MnSi. Physics-Uspekhi (Uspekhi Fizicheskikh Nauk (UFN) Journal). 2011-11-30, 54 (11): 1117–1130. Bibcode:2011PhyU...54.1117S. doi:10.3367/ufne.0181.201111b.1157.  Watanabe, Hideki; Tazuke, ichi; Nakajima, Haruo. Helical Spin Resonance and Magntization Measurement in Itinerant Helimagnet FexCo1−xSi (0.3≤x≤0.85). Journal of the Physical Society of Japan (Physical Society of Japan). 1985, 54 (10): 3978–3986. Bibcode:1985JPSJ...54.3978W. doi:10.1143/jpsj.54.3978.  Bannenberg, L. J.; Kakurai, K.; Falus, P.; Lelièvre-Berna, E.; Dalgliesh, R.; et al. Universality of the helimagnetic transition in cubic chiral magnets: Small angle neutron scattering and neutron spin echo spectroscopy studies of FeCoSi. Physical Review B. 2017, 95 (14): 144433. Bibcode:2017PhRvB..95n4433B. arXiv:1701.05448 . doi:10.1103/physrevb.95.144433.  Seki, S.; Yu, X. Z.; Ishiwata, S.; Tokura, Y. Observation of Skyrmions in a Multiferroic Material. Science (American Association for the Advancement of Science (AAAS)). 2012, 336 (6078): 198–201. Bibcode:2012Sci...336..198S. PMID 22499941. doi:10.1126/science.1214143.  Palmer, S. B.; Baruchel, J.; Farrant, S.; Jones, D.; Schlenker, M. Observation of Spiral Spin Antiferromagnetic Domains in Single Crystal Terbium. Boston, MA: Springer US. 1982: 413–417. ISBN 978-1-4613-3408-8. doi:10.1007/978-1-4613-3406-4_88.  Herz, R.; Kronmüller, H. Field-induced phase transitions in the helical state of dysprosium. Physica Status Solidi A (Wiley). 1978, 47 (2): 451–458. Bibcode:1978PSSAR..47..451H. doi:10.1002/pssa.2210470215.  Tindall, D. A.; Steinitz, M. O.; Kahrizi, M.; Noakes, D. R.; Ali, N. Investigation of the helimagnetic phases of holmium in ac‐axis magnetic field. Journal of Applied Physics (AIP Publishing). 1991, 69 (8): 5691–5693. Bibcode:1991JAP....69.5691T. doi:10.1063/1.347913.