Table of Contents Author Guidelines Submit a Manuscript
Journal of Spectroscopy
Volume 2017 (2017), Article ID 8276520, 6 pages
https://doi.org/10.1155/2017/8276520
Research Article

A Low-Field Temperature Dependent EPR Signal in Terraced MgO:Mn2+ Nanoparticles: An Enhanced Zeeman Splitting in the Wide-Bandgap Oxide

Global Frontier Center for Multiscale Energy Systems, Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Republic of Korea

Correspondence should be addressed to Peter V. Pikhitsa

Received 15 November 2016; Accepted 9 January 2017; Published 19 January 2017

Academic Editor: Javier Garcia-Guinea

Copyright © 2017 Peter V. Pikhitsa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Mn2+ ion doping is used as an electron paramagnetic resonance (EPR) probe to investigate the influence of low-coordination structural defects such as step edges at the surface of terraced (001) MgO nanoparticles on the electronic properties. Beside the well-known hyperfine sextet of Mn2+ ions in the cubic crystal field of MgO, an additional EPR feature with a striking nonmonotonous temperature dependent shift of the -factor is observed in terraced nanoparticles in the temperature range from 4 K to room temperature. By linking the difference in the temperature dependence of the Mn2+ sextet intensity in cubic and terraced nanoparticles with the possible s-d exchange shift and enhanced Zeeman splitting we conclude that the novel EPR feature originates from the loosely trapped charge-compensating carriers at the abundant structural defects at the surface of terraced nanoparticles due to their exchange interaction with neighboring Mn2+ ions.