The beta decays Mn-68 -> Fe-68 -> Mn-69 -> Fe-69 and Mn-70 -> Fe-70 have been measured at the RIBF facility at RIKEN using the EURICA gamma spectrometer combined with an active stopper consisting of a stack of Si detectors. The nuclei were produced as fission fragments from a beam of U-238 at a bombarding energy of (345) MeV/nucleon impinging on a Be target and selected using the BigRIPS separator. Half-lives and beta-delayed neutron emission probabilities have been extracted for these decays, together with first experimental information on excited states populated in Fe-69,Fe-70. The data indicate a continuously increasing deformation for Fe isotopes up to A = 70. This is interpreted, as for Cr isotopes, in terms of the interplay between the quadrupole correlations of the nu 1d(5/2) and nu 0g(9/2) orbitals and the monopole component of the pi 0f(7/2)-nu 0f(5/2) interaction. (C) 2015 The Authors. Published by Elsevier B.V.