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Title: Room temperature d{sup 0} ferromagnetism in ZnS nanocrystals

Abstract

Room temperature ferromagnetic semiconductors have a great deal of advantage because of their easy integration into semiconductor devices. ZnS nanocrystals (NCs), bulk, and surfaces exhibit d{sup 0} ferromagnetism at room temperature. The experiments reveal that NC ferromagnetism takes place at low and room temperatures only due to Zn vacancies (S vacancies do not contribute). To understand the mechanism of d{sup 0} ferromagnetism, we introduce the surface-bulk model of a nanocrystal, which includes both surface and bulk magnetizations. The calculations demonstrate that the surface has the higher than bulk magnetization. We find the mechanism of the ferromagnetism is due to sulfur s- and p-electrons in a tetrahedral crystal field. The bulk magnetic moment increases with Zn vacancy concentration at small concentrations and then goes down at larger concentrations. A surface magnetic moment behaves differently with the concentration. It is always a monotonically rising function. We find that the total NC magnetic moment increases with the size and concentration of Zn vacancies (only low concentrations). We also study the magnetization per unit cell where we find that it decreases for the surface and increases for bulk magnetism with the NC size.

Authors:
; ; ;  [1]
  1. Department of Physics and Astronomy/3905, University of Wyoming, 1000 E. University Avenue, Laramie, Wyoming 82071 (United States)
Publication Date:
OSTI Identifier:
22596781
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 22; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABUNDANCE; CONCENTRATION RATIO; CRYSTAL FIELD; CRYSTALS; ELECTRONS; FERROMAGNETISM; MAGNETIC MOMENTS; MAGNETIZATION; NANOSTRUCTURES; SEMICONDUCTOR DEVICES; SEMICONDUCTOR MATERIALS; SULFUR; SURFACES; TEMPERATURE RANGE 0273-0400 K; VACANCIES; ZINC SULFIDES

Citation Formats

Proshchenko, Vitaly, Horoz, Sabit, Tang, Jinke, and Dahnovsky, Yuri, E-mail: yurid@uwyo.edu. Room temperature d{sup 0} ferromagnetism in ZnS nanocrystals. United States: N. p., 2016. Web. doi:10.1063/1.4953592.
Proshchenko, Vitaly, Horoz, Sabit, Tang, Jinke, & Dahnovsky, Yuri, E-mail: yurid@uwyo.edu. Room temperature d{sup 0} ferromagnetism in ZnS nanocrystals. United States. doi:10.1063/1.4953592.
Proshchenko, Vitaly, Horoz, Sabit, Tang, Jinke, and Dahnovsky, Yuri, E-mail: yurid@uwyo.edu. 2016. "Room temperature d{sup 0} ferromagnetism in ZnS nanocrystals". United States. doi:10.1063/1.4953592.
@article{osti_22596781,
title = {Room temperature d{sup 0} ferromagnetism in ZnS nanocrystals},
author = {Proshchenko, Vitaly and Horoz, Sabit and Tang, Jinke and Dahnovsky, Yuri, E-mail: yurid@uwyo.edu},
abstractNote = {Room temperature ferromagnetic semiconductors have a great deal of advantage because of their easy integration into semiconductor devices. ZnS nanocrystals (NCs), bulk, and surfaces exhibit d{sup 0} ferromagnetism at room temperature. The experiments reveal that NC ferromagnetism takes place at low and room temperatures only due to Zn vacancies (S vacancies do not contribute). To understand the mechanism of d{sup 0} ferromagnetism, we introduce the surface-bulk model of a nanocrystal, which includes both surface and bulk magnetizations. The calculations demonstrate that the surface has the higher than bulk magnetization. We find the mechanism of the ferromagnetism is due to sulfur s- and p-electrons in a tetrahedral crystal field. The bulk magnetic moment increases with Zn vacancy concentration at small concentrations and then goes down at larger concentrations. A surface magnetic moment behaves differently with the concentration. It is always a monotonically rising function. We find that the total NC magnetic moment increases with the size and concentration of Zn vacancies (only low concentrations). We also study the magnetization per unit cell where we find that it decreases for the surface and increases for bulk magnetism with the NC size.},
doi = {10.1063/1.4953592},
journal = {Journal of Applied Physics},
number = 22,
volume = 119,
place = {United States},
year = 2016,
month = 6
}
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