Dependence of the physical properties of $N{d}_{0.5}C{a}_{0.5}Mn{O}_{3+\delta }$ on the oxydation state of $Mn$

We present a comparative study of the magnetic, transport and structural properties of $N{d}_{0.5}C{a}_{0.5}Mn{O}_{3+\delta }$ [$\delta =$ 0.02(1) and 0.04(1)]. We have found significant differences between the low temperature magnetic orders and the magnetization curves below $T_{CO}\approx 250K$ of the two samples. In particular one component of the magnetic moment presents a ferromagnetic coupling between the $(001)$ planes ($Pbnm$ setting) deviating the angle between neighboring $Mn$ ions from ${180}^o$ (perfect CE order) to ${150}^o$ [$\delta =0.02(1)$] and ${130}^o$ [$\delta =0.04(1)$]. These results imply a remarkable $\delta$ dependence which is discussed in the light of a non-random spatial distribution of defects in the perfect charge order scheme.