Magnetic structure of YBaMnO4The manganese oxides are attractive compounds for their magnetic properties in magnetoresistive or improper ferroelectric multiferroic compounds. The Jahn-Teller trivalent manganese allows antiferromagnetic or ferromagnetic interactions by orbital ordering. Up to day, there is no structure with a pure ferromagnetic interaction between trivalent manganese ions. We synthesized a new structure, YBaMnO4, which should exhibit pure ferromagnetic coupling between trivalent manganese. The aim of this propasal is to characterize the magnetic structure of this compound by powder neutron diffraction.