TbMnO3 attracts special attention due to its large magnetoelectric coupling, polarization flop and ferro-paramagnetic phase transition, both induced by magnetic field. Despite the extensive research, the role of the lattice distortions and spin arrangement in the stabilization of polarization is not fully understood. This can be achieved by studying B-site substituted TbMnO3 by non-Jahn-Teller active Fe3+. This proposal aims at unravelling the effect of Fe3+ substitution in the magnetoelectric properties of the TbMn0.98Fe0.02O3 by single crystal neutron diffraction, as a function of temperature and magnetic field, in order to ascertain the changes of both crystalline and magnetic structures, which affects the ferroelectric properties. This information will enable to unravel the spin structure and structural distortions induced by the magnetic field, through the spin- lattice coupling.