Preparation and magnetoresistance of Ag 2+x Se thin films deposited via Pulsed Laser Deposition

TL;DR

This study reports the fabrication of dense, uniform Ag 2+x Se thin films via pulsed laser deposition, revealing their microstructure and the relationship between silver precipitates and large linear magnetoresistance effects.

Contribution

It introduces a method to produce high-quality Ag 2+x Se thin films and links their microstructure, especially silver precipitates, to their magnetoresistance properties.

Findings

Films are dense, uniform, and defect-free.

Presence of silver precipitates correlates with large linear magnetoresistance.

Identification of a potentially metastable phase of silver selenide.

Abstract

The preparation of Ag 2+x Se thin films with thicknesses between 4 nm and 3000 nm by pulsed laser deposition on single crystalline NaCl and MgO substrates is reported. The films are perfectly dense and show a good lateral uniformity with a small number of defects. The microstructure of the films corresponds to a nanoparquet, being composed of two different phases of silver selenide. One phase is identified as the Naumannite low temperature phase of silver selenide, the structure of the other phase has not been reported in detail before and probably represents a metastable phase. Silver-rich films contain silver precipitates with typical sizes on the nanoscale. Their presence and their size appears to be responsible for the large and linear magnetoresistance effect of silver-rich silver selenide.