Observation of disorder induced weak localization in Gd:ZnO thin films

We have observed weak localization induced by disorder in thin films of Gd doped ZnO (Gd:ZnO) deposited by pulsed laser deposition (PLD). Disorder parameter (K(f)l) of all the Gd:ZnO thin films was found to be greater than 1, which indicates that thin films of Gd:ZnO in this study are in metallic side of metal-insulator transition. However, temperature dependent resistivity studies of all the Gd:ZnO thin films exhibits negative temperature coefficient of resistance (TCR) showing semiconductor like nature at low temperatures. This anomaly in temperature dependent resistivity behaviour has been attributed to the dominant presence of weak localization. Magnetoresistance measurements confirms the dominant influence of weak localization in the conducting mechanism of Gd:ZnO films. Phase coherent length was found to be varied with the concentration of Gd and reports the highest value at similar to 360 nm for Gd:ZnO thin film with 1 at.% of Gd concentration.

Automated summary

The study found that Gd doped ZnO thin films are on the metallic side of the metal-insulator transition, but exhibit semiconductor properties at low temperatures. Weak localization plays a dominant role in the behavior of these films, and the phase coherent length varies with Gd concentration.