Structural correlation to enhanced magnetodielectric properties of Pr-doped polycrystalline Gd0.55Pr0.45MnO3 at low temperatures

Abstract

The effect of improved dielectric properties in the presence of an applied magnetic field is discussed in polycrystalline Gd0.55Pr0.45MnO3 complemented by the structural and magnetic properties. Enhanced dielectric permittivity and low dielectric loss represent the strongly field-dependent dielectric behaviour of the sample. The structural characterizations using synchrotron angle dispersive X-ray diffraction confirm the orthorhombic symmetry of the polycrystalline sample with the Pnma space group in the temperature range from 300 K to 50 K. There is no structural transition observed at lower temperatures down to 50 K; however the Mn- O octahedral distortion is slightly reduced. The magneto-dielectric measurements were performed in the frequency range 500 Hz–1 MHz and temperature range 8 K–300 K both with and without external magnetic field (up to 7 Tesla), which shows the high dielectric constant. The magnetic study shows the negative magnetization and high coercivity in Gd0.55Pr0.45MnO3 at low temperatures due to competition in between spin ordering of Mn and Gd + Pr magnetic lattice. The MnOMn bond angle study indicates the A-type antiferromagnetic structure of the material at lower temperature.