Ferromagnetic and reetrant spin-glass state in La$_{0.7}$Ca$_{0.3}$Mn$_{1-y}$V$_{y}$O$_{3}$

We have investigated the influence of vanadium (V)-doping on the electronic and the magnetic properties of La$_{0.7}$Ca$_{0.3}$Mn$_{1-y}$V$_ {y}$O$_{3}$ prepared by the conventional solid state reaction. The resistivity upturn below the Curie temperature was observed in the V-doped manganites with 0.1 $\leq $ y $\leq $ 0.2 due to the orbital ordering (OO). The V doping into the Mn sites results in an increase of the ferromagnetic (FM) superexchange interaction favoring the ferromagnetic insulating (FMI) phase. The magnetic relaxation of the explored compounds is found in both reentrant spin glass and high-temperarure FM phases. The heavy V -doping in the La$_{0.7} $Ca$_{0.3}$MnO$_{3}$ compound induces the reentrant behavior due to formation of OO FMI regions.