Ferromagnetic behavior of ultrathin manganese nanosheets

Abstract

Ferromagnetic behavior has been observed experimentally for the first time in nanostructured manganese. Ultrathin (~0.6-nm) manganese nanosheets were synthesized inside the two-dimensional channels of sol-gel-derived Na-4 mica. The magnetic properties of the confined system were measured within the 2-300 K temperature range. The confined structure was found to show a ferromagnetic behavior with a nonzero coercivity value. The coercivity value remained nonzero throughout the entire temperature range of measurement. The experimental variation of the susceptibility as a function of temperature can be satisfactorily explained on the basis of a two-dimensional system with a Heisenberg Hamiltonian involving direct exchange interaction.