Center for Functional Nanomaterials Seminar

Frustrated interactions appear throughout the physical world, defined by an inability to simultaneously minimise the energy of all pair-wise bonds within a system. The physics of such systems has recently found a new arena in the field of nanomagnetism. Well defined anisotropies in ferromagnetic nanoelements can be exploited to locally confine single domain dipole moments to conflicting Ising-like axes over structurally ordered patterns, forming model 2D systems analogous to real geometrically frustrated magnets e.g. spin-ice. One possible realisation is the magnetic square ice system, a grid of elongated nanobars, ~ 100 nm in size, that form an array of interlinked cross-shaped vertices. After presenting a brief introduction to the field, I will discuss our recent work studying thermal and field ordering in the square ice system, the magnetic force microscopy observation of magnetic "monopole"-like defects and their energetics, and preliminary off-specular synchrotron x-ray resonant magnetic scattering data.