@article{087f85fa92854fa398b3ac5d53c41c67,
title = "Anisotropic Magnetic Resonance in Random Nanocrystal Quantum Dot Ensembles",
abstract = "Magnetic anisotropy critically determines the utility of magnetic nanocrystals (NCs) in new nanomagnetism technologies. Using angular-dependent electron magnetic resonance (EMR), we observe magnetic anisotropy in isotropically arranged NCs of a nonmagnetic material. We show that the shape of the EMR angular variation can be well described by a simple model that considers magnetic dipole-dipole interactions between dipoles randomly located in the NCs, most likely due to surface dangling bonds. The magnetic anisotropy results from the fact that the energy term arising from the magnetic dipole-dipole interactions between all magnetic moments in the system is dominated by only a few dipole pairs, which always have an anisotropic geometric arrangement. Our work shows that magnetic anisotropy may be a general feature of NC systems containing randomly distributed magnetic dipoles. ",
author = "Almeida, {Ant{\'o}nio J.S.} and Ayaskanta Sahu and Norris, {David J.} and Kakazei, {Gleb N.} and Haripriya Kannan and Brandt, {Martin S.} and Martin Stutzmann and Pereira, {Rui N.}",
note = "Funding Information: This work has been funded by FCT via projects no. PTDC/280/FIS/112885/2009, no. RECI/FIS-NAN/0183/2012, no. UID/CTM/50025/2019, no. NORTE-01-0145-FEDER-022096, and no. MIT-EXPL/IRA/0012/2017 and Grant SFRH/BD/79223/2011, by the Swiss National Science Foundation under award no. 200021-140617, and by Funda{\c c}{\~a}o Calouste Gulbenkian via Pr{\'e}mio de Est{\'ı}mulo {\`a} Investiga{\c c}{\~a}o. This work has been also developed in the scope of the Project i3N (project no. UID/CTM/50025/2019), financed by national funds through the Funda{\c c}{\~a}o para a Ci{\^e}ncia e a Tecnologia/Minist{\'e}rio da Educa{\c c}{\~a}o e Ci{\^e}ncias (FCT/MEC) and when applicable cofinanced by FEDER under the PT2020 Partnership Agreement, and the Project i3N, UIDB/50025/2020 and UIDP/50025/2020, financed by national funds through the FCT/MEC. G.N.K. acknowledges the Network of Extreme Conditions Laboratories-NECL. H.K. has been (partially) supported by the Schlumberger Foundation Faculty for the Future Program. We gratefully acknowledge support for instrument use, scientific and technical assistance from the Imaging Facility of CUNY Advanced Science Research Center, NYU shared Instrumentation Facility through the Materials Research Science and Engineering Center (MRSEC) and MRI programs of the National Science Foundation under award numbers DMR-1420073 and DMR-0923251. We are grateful for the assistance of Tony Hu at the Department of Chemistry of New York University with the X-ray analysis, and we thank the support to the X-ray facility by the National Science Foundation under Award Numbers CRIF/CHE-0840277 and by the NSF MRSEC Program under award numbers DMR-0820341 and DMR-1420073. a Publisher Copyright: Copyright {\textcopyright} 2020 American Chemical Society.",
year = "2020",
month = may,
day = "26",
doi = "10.1021/acsomega.0c00279",
language = "English",
volume = "5",
pages = "11333--11341",
journal = "ACS Omega",
publisher = "American Chemical Society",
number = "20",
}