Universal critical behavior in polycrystalline La0.75Ca0.25-xNaxMnO3 (x = 0.00; 0.05) samples Souhir Bouzidi, Manel Dhahri, J. Dhahri and E. K. Hlil Eur. Phys. J. Plus, 136 1 (2021) 23 Published online: 03 January 2021 DOI: 10.1140/epjp/s13360-020-00958-9