High-field electron paramagnetic resonance as a microscopic probe of anisotropic strain at Mn 2+ sites in CdSe:Mn 2+ quantum dots

Zhenxing Wang, Weiwei Zheng, Johan Van Tol, Naresh S. Dalal, Geoffrey F. Strouse

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

High-frequency electron paramagnetic resonance (HF-EPR) provides a contactless microscopic probe of magnetic impurities and their surroundings in nanoparticles. In 5.0 nm colloidally prepared CdSe quantum dots (QDs) containing 0.6% Mn 2+, a core and a surface site can be readily distinguished on the basis of g-factor and 55Mn hyperfine interaction. In contrast to EPR in the bulk, at low temperatures a broad background signal develops, which at high fields is the only remaining feature. Previous studies have suggested this background signal originates from exchange coupled Mn 2+ clusters arising from spinodal decomposition; HF-EPR shows that it is due to strain-broadening of the zero-field splitting related to local lattice distortions within the QD.

Original languageEnglish (US)
Pages (from-to)73-77
Number of pages5
JournalChemical Physics Letters
Volume524
DOIs
StatePublished - Feb 6 2012
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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