Magnetic meta-materials exhibit interesting and complex magnetisation behaviour which originates from nanoscale patterning in addition to the magnetic material. Artificial spin ice is one example, where interconnected magnetic nanobars are arranged in a kagome network. Here, the collective behaviour originates from the ‘ice rules’ local ordering principle and also magnetic domain wall (DW) effects[1,2]. The structures are rather interesting for data storage if a methodology can be developed to controllably select a single microstate of the array[3].

Here we explore spatially selective methods of magnetization reversing within the array, including selective domain wall propagation[1,2] off-axis global fields[4] and injection of domain walls with locally applied fields from striplines and an MFM tip. The spatially resolved magnetisation reversal behaviour is imaged using MFM and focussed MOKE magnetometry. This research builds on our understanding of complex interconnected magnetic systems and opens pathways to further explore the manipulation of magnetic charges[5] and potential technological applications.

[1] S. K. Walton et al. New Journal of Physics 17, 013054, (2015).
[2] K. Zeissler et al. Sci Rep-Uk 3, 1252, (2013).
[3] A. Pushp et al. Nature Physics 9, 505-511, (2013).
[4] D. M. Burn et al. Phys. Rev. B 92, 214425, (2015).
[5] S. Ladak et al. Nature Physics 6, 359-363, (2010).

We acknowledge Leverhulme Trust grant RPG_2012-692 and UK EPSRC grant EP/G004765/1 for funding.