Tuning magnetic order in artificial kagome spin ice

Thermally active artificial spin ice promised the direct observation of magnetic ordering and the degree of magnetic order that can be achieved depends on two temperature scales. The superparamagnetic blocking temperature of the individual nanomagnets [1] and the phase transition temperature of the system [2]. The interplay between these two temperature scales dictates the observable magnetic phases in experiments. Here, I will discuss how both the phase transition temperature in artificial kagome ice and the superparamagnetic blocking temperature of nanomagnets can be tuned. This gives rise to the magnetic ground state in seven-ring structures and extended systems.



Specifically, I will focus on the fabrication of nanomagnetic bridges, placed asymmetrically at the vertices, to control the degree of frustration in the system [3]. We obtain various degrees of magnetic ordering and two phases. We then utilize the thermally active system to show that we can image a phase transition using temperature-dependent X-ray photoemission electron microscopy. The frustration is quantified to show why certain artificial spin ice systems can, or have not yet,m been seen in their magnetic ground states.



Reference:

[1] K. Hofhuis, A. Hrabec, H. Arava, N. Leo, Y.L. Huang, R.V. Chopdekar, S. Parchenko, A. Kleibert, S. Koraltan, C. Abert, C. Vogler, D. Suess, P.M. Derlet, & L.J. Heyderman, Physical Review B 102, 180405(R) (2020)

[2] G. Moller & R. Moessner, Physical Review B 80, 140409(R) (2009).

[3] K. Hofhuis, S. H. Skjærvø, S. Parchenko, H. Arava, Z. Luo, A. Kleibert, P. M. Derlet, & L. J. Heyderman, Nature Physics 18, 699 (2022)