Magnetic phase transition and magneto-elastic coupling in Fe1+xCr2-xSe4 (x = 0.0 - 0.50)

•The magnetic state is tuned from antiferromagnetic (AFM) to ferrimagnetic (FRI) in the Fe1+xCr2-xSe4 (x = 0 - 0.50) series.•Fe substitution leads to a lattice contraction without alteration of crystal symmetry.•The evolution of AFM to FRI transformation occurs through an intermediate state with coexisting AFM and FRI phases.•The magnetic ordering is accompanied by an anisotropic lattice distortion.•It shows magnetocaloric effect across the magnetic transition.