Reversal magnetization, spin reorientation, and exchange bias in YCrO3 doped with praseodymium

Crystal structure, thermal properties, and magnetic properties were studied systematically in Y1-xPrxCrO3 with 0.0 <= x <= 0.3 compositions. Magnetic susceptibility and specific-heat measurements show an increase in the antiferromagnetic transition temperature (T-N) as Pr is substituted in the Y sites and notable magnetic features are observed below T-N. Strong coupling between magnetic and crystalline parameters is observed in a small range of Pr compositions. A small perturbation in the lattice parameters by a Pr ion is sufficient to induce a spin-reorientation transition followed by magnetization reversal to finally induce the exchange-bias effect. The spin-reorientation temperature (T-SR) is increased from 35 to 149 K for 0.025 <= x <= 0.1 compositions. It is found that the Cr spin sublattice rotates continuously from TSR to a new spin configuration at lower temperature. In addition, magnetization reversal is observed at T* similar to 35K for x = 0.05 up to T* similar to 63K for x = 0.20 composition. The M-H curves show a negative exchange-bias effect induced by Pr ions, which are observed below 100 K and are more intense at 5 K. At 10 K, the magnetic contribution of the specific heat as well as the ZFC magnetization show the rise of a peak with increasing Pr content. The magnetic anomaly could be associated with the freezing of the Pr magnetic moment randomly distributed at the 4c crystallographic site. A clear correspondence between spin reorientation, magnetization reversal, and exchange-bias anisotropy with the tilting and octahedral distortion is also discussed.