Magnetic properties of self-assembled ferritin-core arrays

We studied the magnetic properties of a ferritin-core array, deposited on a Si wafer and encapsulated in silica. The array was formed by a simple evaporation-induced self-assembly mechanism of ferritin proteins, and it consists of 6 nm ferritin cores crystallized in a two-dimensional hexagonal lattice with a core-core distance of about 10.5 nm. Magnetization studies indicate that the array undergoes a magnetic transition around 210 K. Our small-angle neutron-scattering studies provide evidence that huge net magnetic moments are stabilized in each core and that long-range magnetic order between the core moments occurs in the array.