  The effect of oxygen content on the magnetic and transport properties of the
ferromagnetic Eu0.9Ca0.1BaCo2O5.5+{\delta} has been carried out. Unlike the
increase in TC with calcium content, paradoxally the TC value decreases with
the increase in oxygen (Co4+) content as observed in the undoped phase. This
result unveils the hidden generic magnetic feature of the LnBaCo2O5.5 system in
the calcium doped phase. This behaviour supports strongly the appearance of
Co3+ disproportion action into Co4+ and Co2+ and the magnetic phase separation
scenario of ferromagnetic domains embedded in an antiferromagnetic matrix. All
the samples covering a wide range of oxygen content, exhibit a p-type
conductivity.
