Comment on “Colossal dielectric and magnetodielectric effect inEr2O3nanoparticles embedded in aSiO2glass matrix”

Abstract

In a recent paper, Mukherjee et al. [Phys. Rev. B 82, 104107 (2010)] reported a colossal enhancement of dielectric constant along with magnetodielectric (MD) behavior in a SiO${}_{2}$-Er${}_{2}$O${}_{3}$ system synthesized via the sol-gel route. In the opinion of the authors of the criticized paper, such a colossal MD effect in the measured samples is a direct consequence of exploiting magnetoresistance changes associated with the size and concentration of Er${}_{2}$O${}_{3}$ nanoparticles. We point out that the disappearing MD behavior depends on the crystallite size and dopant concentration, as shown by the authors of the criticized paper, but also on the nature and the crystal structure of the compound.