Theoretical study of the exchange interaction and the exchange force between Fe films: Feasibility of exchange force microscopy

A theoretical study of the exchange interaction and the exchange force betw een two magnetic Fe(001) films based on a first-principles calculation is r eported. Our calculations are carried out by varying the separation between the surface of two films from 1.4 to 5.0 Angstrom. In these separations, w e observed strong distance dependences of the exchange interaction and the exchange force. The variation in the exchange interaction and the exchange force relative to the atomic site on the surface are significant. Based on these results, the feasibility of exchange force microscopy (EFM) which pro bes the exchange force between the tip and the sample is discussed.