Magnetoelastic interaction in a ferromagnet-multiferroic system

The contribution of the elastic interaction to the total interaction energy of a ferromagnetic nanolayer with a BiFeO$_3$ multiferroic nanolayer has been investigated. It has been shown that this contribution amounts to less than 10% and the main contribution to the energy comes from the exchange interaction. The lower limit for the minimum size of a bit of magnetoresistive memory with electric-field writing (magnetoelectric random-access memory (MERAM)), which is associated with the existence of a superparamagnetic limit, has been found. If the writing is based on exchange interaction between the ferromagnetic and electrosensitive layers, the minimum bit size is 7 nm, which indicates prospects for this type of MERAM.