Role of multivalent state of B-site cations on the electrical transport behavior of Zn-substituted double perovskite: La2CuMnO6

The localization and delocalization of charge carriers considerably affect the ceramic's electrical transport characteristics. These phenomena depend on the cationic charge states, grain growth, crystal geometry, etc. Doping of similar cationic charge states and comparative ionic radii cations are expected to alter the crystal geometry only. In contrast, exciting features are reflected in the results when such substitution affects the cationic valance states. Our previous work reported the structural, electronic, dielectric, and magnetic behavior of Zn-doped La$_2$CuMnO$_6$ (LCM) [1]. A complex coordination state of B-site cations produced tilt in the crystal geometry, diffused relaxor behavior in dielectric response, and non-colinearity in the antiferromagnetic behavior of these oxides. However, the extent of cationic charge states and their effect on ceramic's electrical transport properties were unraveled. This work reassembles the synergistic role of cationic charge states and their corresponding interactions on the electrical transport behavior of LCM, La$_2$Cu$_0.5$Zn$_0.5$MnO$_6$ (LCZM), and La$_2$ZnMnO$_6$ (LZM). The detailed analysis of AC- and DC- conductivity depicted the shift of long-range dynamics to short-range dynamics with Zn-substitution under the influence of temperature and frequency.