Observation of magnetic vortex pairs at room temperature in a planar α-Fe2O3/Co heterostructure

被引:93
作者
Chmiel, F. P. [1 ]
Price, N. Waterfield [1 ]
Johnson, R. D. [1 ]
Lamirand, A. D. [2 ]
Schad, J. [3 ]
van der Laan, G. [2 ]
Harris, D. T. [3 ]
Irwin, J. [4 ]
Rzchowski, M. S. [4 ]
Eom, C-B [3 ]
Radaelli, P. G. [1 ]
机构
[1] Univ Oxford, Dept Phys, Clarendon Lab, Oxford, England
[2] Diamond Light Source, Harwell Sci & Innovat Campus, Didcot, Oxon, England
[3] Univ Wisconsin, Dept Mat Sci & Engn, 1509 Univ Ave, Madison, WI 53706 USA
[4] Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA
基金
英国工程与自然科学研究理事会;
关键词
ABSORPTION; SPECTRA;
D O I
10.1038/s41563-018-0101-x
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Vortices, occurring whenever a flow field 'whirls' around a one-dimensional core, are among the simplest topological structures, ubiquitous to many branches of physics. In the crystalline state, vortex formation is rare, since it is generally hampered by long-range interactions: in ferroic materials (ferromagnetic and ferroelectric), vortices are observed only when the effects of the dipole-dipole interaction are modified by confinement at the nanoscale(1-3), or when the parameter associated with the vorticity does not couple directly with strain(4). Here, we observe an unprecedented form of vortices in antiferromagnetic haematite (alpha-Fe2O3) epitaxial films, in which the primary whirling parameter is the staggered magnetization. Remarkably, ferromagnetic topological objects with the same vorticity and winding number as the alpha-Fe2O3 vortices are imprinted onto an ultra-thin Co ferromagnetic over-layer by interfacial exchange. Our data suggest that the ferromagnetic vortices may be merons (half-skyrmions, carrying an out-of plane core magnetization), and indicate that the vortex/meron pairs can be manipulated by the application of an in-plane magnetic field, giving rise to large-scale vortex-antivortex annihilation.
引用
收藏
页码:581 / +
页数:6
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