skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Room temperature d 0 ferromagnetism in ZnS nanocrystals

Authors:
; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1256538
Grant/Contract Number:
DEFG02-10ER46728
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 119; Journal Issue: 22; Related Information: CHORUS Timestamp: 2016-12-21 06:19:08; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Proshchenko, Vitaly, Horoz, Sabit, Tang, Jinke, and Dahnovsky, Yuri. Room temperature d 0 ferromagnetism in ZnS nanocrystals. United States: N. p., 2016. Web. doi:10.1063/1.4953592.
Proshchenko, Vitaly, Horoz, Sabit, Tang, Jinke, & Dahnovsky, Yuri. Room temperature d 0 ferromagnetism in ZnS nanocrystals. United States. doi:10.1063/1.4953592.
Proshchenko, Vitaly, Horoz, Sabit, Tang, Jinke, and Dahnovsky, Yuri. 2016. "Room temperature d 0 ferromagnetism in ZnS nanocrystals". United States. doi:10.1063/1.4953592.
@article{osti_1256538,
title = {Room temperature d 0 ferromagnetism in ZnS nanocrystals},
author = {Proshchenko, Vitaly and Horoz, Sabit and Tang, Jinke and Dahnovsky, Yuri},
abstractNote = {},
doi = {10.1063/1.4953592},
journal = {Journal of Applied Physics},
number = 22,
volume = 119,
place = {United States},
year = 2016,
month = 6
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4953592

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

Save / Share:
  • Colloidal cobalt-doped TiO{sub 2} (anatase) nanocrystals were synthesized and studied by electronic absorption, magnetic circular dichroism, transmission electron microscopy, magnetic susceptibility, cobalt K-shell X-ray absorption spectroscopy, and extended X-ray absorption fine structure measurements. The nanocrystals were paramagnetic when isolated by surface-passivating ligands, weakly ferromagnetic (M{sub s} {approx} 1.5 x 10{sup -3} {micro}{sub B}/Co{sup 2+} at 300 K) when aggregated, and strongly ferromagnetic (up to M{sub s} = 1.9 {micro}{sub B}/Co{sup 2+} at 300 K) when spin-coated into nanocrystalline films. X-ray absorption data reveal that cobalt is in the Co{sup 2+} oxidation state in all samples. In addition to providing strongmore » experimental support for the existence of intrinsic ferromagnetism in cobalt-doped TiO{sub 2}, these results demonstrate the possibility of using colloidal TiO{sub 2} diluted magnetic semiconductor nanocrystals as building blocks for assembly of ferromagnetic semiconductor nanostructures with potential spintronics applications.« less
  • 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 sulfurmore » 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.« less
  • The effects of substitution of Ca by Ba in La{sub 1{minus}x}Ca{sub x}MnO{sub 3} (LCMO) with x{lt}0.5 were investigated systematically in order to clarify the role of the size of the A cations. As for the La{sub 1{minus}x}(Ba{endash}Ca){sub x}MnO{sub 3} (LBCMO) films of ferromagnetic metallic (FMM) region (x=0.2; 0.3; and 0.4), by doping Ba, the ferromagnetic transition temperature (T{sub C}) and the insulator-to-metal (IM) transition temperature (T{sub IM}) were improved about 30{endash}60 K, compared with those of LCMO thin films with the same ratio of Mn{sup 3+}:Mn{sup 4+}. Especially, La{sub 0.7}Ba{sub 0.1}Ca{sub 0.2}MnO{sub 3} thin films have an anomalously high T{submore » C} (about room temperature) and a T{sub IM} of 275 K under zero field. In the ferromagnetic insulating (FMI) region (x=0.15; 0.1), the Ba doping enables the IM transition and remarkably heightens the T{sub C} as well. The phase diagram shows that in the slightly doped region (x{lt}0.5), Ba doping has made the FMM phase significantly expanded. {copyright} 2001 American Institute of Physics.« less
  • No abstract prepared.
  • Ferromagnetism is observed at room temperature, when a small percentage (5%) of non-magnetic titanium is added to zinc atoms to form Ti-doped ZnO nanoclusters in the oxygen atmosphere. The nanocluster films are prepared at room temperature by a technique that is a combination of high pressure sputtering along with aggregation. A Super-conducting Quantum Interference Device (SQUID) measures the magnetic properties of this cluster films at various temperatures. Ti dopant exhibits +4 oxidation state through out the cluster film. Coercivity of the samples decreased exponentially with the increase of temperature.