As new information and communication technologies boom, the energy consumption of data processing and storage systems has become a major issue. The limits of state of the art systems regarding this gives rise to the need for ground-breaking ultra-low power technologies.This PhD thesis suggests an original approach of this issue, based on a bistable composite magnetoelectric element (piezoelectric/magnetostrictive) which can be controlled unequivocally, named MELRAM.The static energetic study shows that the combination of an uniaxial anisotropy and a static magnetic bias field defines two stable and perpendicular equilibrium positions for magnetization in the magnetostrictive part. The application of piezoelectric stress allows the electric control of the magnetization position.The energetic study also shows the long term (10 years) stability of the system, in a large temperature range around room temperature, with an energy barrier of 60kBT. The dynamic study, using the macrospin model, gives a response time less than 1ns. The dissipated energy during writing, of electric and magnetic origin, is estimated at 261kBT (1.1aJ), that is to say four orders of magnitude below the state of the art.Several reading strategies using spin valves and magnetic tunnel junction are proposed and commented. First realization of nanometer-sized magnetostrictive elements are presented as well as an integrated polarization solution, using permanent magnets
