Geometric Frustration and Long-range Ordering Induced by Surface Pressure Oscillation in a Langmuir Blodgett Monolayer of Magnetic Soft Spheres

As a step toward the bottom-up construction of magnonic systems, this paper demonstrates the use of a large-amplitude surface-pressure annealing technique to generate 2-D order in a LangmuirBlodgett monolayer of magnetic soft spheres comprising a surfactant-encapsulated polyoxometalate. The films show a distorted square lattice interpreted as due to geometric frustration caused by 2-D confinement between soft walls, one being the air interface and the other the aqueous subphase. Hysteresis and relaxation phenomena in the 2-D layers are suggested to be due to folding and time-dependent interpenetration of surfactant chains.