Dielectric relaxation in a new double perovskite oxide Ho2MgZrO6

A new double perovskite oxide holmium magnesium zirconate Ho2MgZrO6 (HMZ) was prepared by solid state reaction technique. The crystal structure has been determined by powder X-ray diffraction which shows monoclinic phase at room temperature with cell parameters a = 9.3028 ± 0.0030 Å, b = 5.2293 ± 0.0008 Å, c = 4.4009 ± 0.0009 Å, β = 103.3746 ± 0.0166°. An analysis of complex permittivity with frequency was carried out assuming a distribution of relaxation times. The frequency dependent electrical data are analyzed in the framework of conductivity and electric modulus formalisms. At the high temperature range, conductivity data satisfy the variable range hopping (VRH) model. In this regime, the conductivity of sample obeys Mott’s T1/4 law, characteristic of VRH. High temperature data indicates the formation of thermally activated small polarons. The scaling behaviour of imaginary part of electric modulus suggests that the relaxation describes the same mechanism at various temperatures.

Graphical abstractPowder X-ray diffraction analysis suggests that the compound crystallizes in monoclinic phase at room temperature described by the P21/n space group with β = 103.3746 ± 0.0166° (a = 9.3028 ± 0.0030 Å, b = 5.2293 ± 0.0008 Å, c = 4.4009 ± 0.0009 Å) and unit cell volume V = 208.29 A3.Figure optionsDownload full-size imageDownload as PowerPoint slide