Super Exchange-Induced Canted Ferromagnetism in Transition Metal-Doped ZnS Quantum Dots
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- 作者：Lalit Kumar Sharma ; Samrat Mukherjee
- 关键词：Dilute magnetic semiconductor ; canted ferromagnetism ; bound magnetic polaron ; super ; exchange interaction
- 刊名：Journal of Electronic Materials
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：46
- 期：2
- 页码：1270-1278
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Optical and Electronic Materials; Characterization and Evaluation of Materials; Electronics and Microelectronics, Instrumentation; Solid State Physics;
- 出版者：Springer US
- ISSN：1543-186X
- 卷排序：46
文摘
ZnS quantum dots doped with magnetic transition metal (Zn1−xTMxS; where x = 0.04, 0.08 and transition metal = Ni, Mn, Fe, Co and Cr) were synthesized using a chemical co-precipitation method. To prevent agglomeration, samples were capped with polyvinylpyrrolidone. X-ray diffraction peaks confirmed pure cubic phases of all samples. The crystallite dimensions of the samples are within the scale of 2.0–2.6 nm, which was calculated using Scherrer formula. A band gap varying from 4.1 eV to 4.24 eV was estimated from their ultraviolet–visible absorption spectroscopy. The synthesized samples show a strong blue shift in their emission spectroscopy along with emissions from inherent Zn and S point defects (interstitial and vacancy). Superconducting quantum interference device studies at 300 K reveal that all samples show room temperature canted ferromagnetism at low magnetic fields which does not saturate even up to a fields of 5 T. We study the defects as seen through emission spectroscopy and correlate with the magnetic properties of the doped semiconducting quantum dots.