# Sign reversal of magnetoresistance and p to n transition in Ni doped ZnO thin film

## TL;DR

This study investigates the magnetoresistance and Hall effect in Ni-doped ZnO thin films, revealing a temperature-dependent transition from hole to electron conduction and demonstrating potential for spintronic applications.

## Contribution

It provides a detailed analysis of the temperature-dependent magnetotransport properties and models the conduction mechanisms in Ni-doped ZnO thin films, highlighting the sign reversal of magnetoresistance.

## Key findings

- Magnetoresistance switches from negative to positive with temperature.
- Hall effect indicates a transition from hole to electron conduction around 50 K.
- Spin polarization of charge carriers observed, useful for spintronics.

## Abstract

We report the magnetoresistance and nonlinear Hall effect studies over a wide temperature range in pulsed laser deposited Ni0.07Zn0.93O thin film. Negative and positive contributions to magnetoresistance at high and low temperatures have been successfully modeled by the localized magnetic moment and two band conduction process involving heavy and light hole subbands, respectively. Nonlinearity in the Hall resistance also agrees well with the two channel conduction model. A negative Hall voltage has been found for T $\gte 50 K$, implying a dominant conduction mainly by electrons whereas positive Hall voltage for T less than 50 K shows hole dominated conduction in this material. Crossover in the sign of magnetoresistance from negative to positive reveals the spin polarization of the charge carriers and hence the applicability of Ni doped ZnO thin film for spintronic applications.