Speaker
Description
Artificial spin systems have facilitated the experimental exploration of classical frustrated spin models, with a particular attention given to the square ice geometry. However, due to the magnetostatic nature of inter-island couplings, most artificial realizations of square spin ice do not fulfill the energetic requirements specific to the celebrated square ice model. Several approaches have been proposed to circumvent this aspect, one of which consists in the systematic removal of the square network elements, yielding a topologically frustrated system that can retrieve the features of the square ice model at a larger lengthscale. The Shakti geometry has been the highlight of this approach, with its two distinctive forms: the Shakti lattice, containing differently sized islands, and the modified Shakti lattice, containing unisized elements. Experimental realizations of both lattice types have retrieved features of the spin ice model. However, the impact of the presence/absence of differently sized elements on the thermal dynamics of the system in a superparamagnetic regime and the development of magnetic order have not been thoroughly explored.
Using delta-doped FePd artificial realizations of the two Shakti lattices, we have characterized and compared the final magnetic configurations of the two network types after submitting them to the same experimental protocol. Using reciprocal space analysis tools, the development of distinctive short-range order in the two lattices can be highlighted. Our results illustrate the potential of tailoring the final magnetic order developed by such thermally-active artificial structures by the appropriate design of their islands sizes.
