Magnetic field dependence of Griffith phase and critical behavior in La0.8Ca0.2MnO3 nanoparticles

•Nanosized La0.8Ca0.2MnO3 crystallizes in the orthorhombic structure with Pnma space group.•Ferromagnetic clusters above Curie temperature has been identified with Griffiths phase.•With the increase of the applied magnetic field strength, the Griffiths phase is suppressed.•Results show that the paramagnetic-ferromagnetic transition is of second order.•The critical exponents values are close to those for the mean-field model.