Superparamagnetic and Perfect-Paramagnetic Zinc Ferrite Quantum Dots from Microwave-Assisted Tunable Synthesis.

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Parmar KPS; Department of Physics, University of Petroleum and Energy Studies (UPES), Dehradun 248007, India.
Kim JH; School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST, Ulsan 44919, South Korea.
Bist A; Department of Science, Atal Utkrisht Government Inter College, Srikot, Uttarkashi 249193, India.
Dua P; College of Applied Sciences, Suhar University of Technology and Applied Sciences, Muscat 133, Oman.
Tiwari PK; Department of Physics, Birla Institute of Technology, Mesra, Ranchi 835215, India.
Phuruangrat A; Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand.
Lee JS; School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST, Ulsan 44919, South Korea.

ACS omega [ACS Omega] 2022 Aug 23; Vol. 7 (35), pp. 31607-31611. Date of Electronic Publication: 2022 Aug 23 (Print Publication: 2022).

English

The properties of quantum dot (QD)-size material depend directly upon its unit cell structure. Spinel zinc ferrite QD powder is produced via a one-pot microwave-assisted hydrothermal synthesis for just 5 min. Varying initial pH values of the preparation sol from 6 to 12 enlarges the Zn/Fe atomic ratio (by ca. 10%), unit cell volume (by ca. 0.5%), particle size (3.5-4.5 nm), and degree of inversion. This leads to a change in the magnetic behavior of the QD-size zinc ferrite from a superparamagnetic to a perfect-paramagnetic type. This novel finding points that the significant changes in the inherent structural parameters of spinel ZnFe 2 O 4 QDs (Zn/Fe ratio and degree of inversion) induced by the systematic pH change of the preparation sol are exclusively responsible for the observed unique magnetic behavior instead of mere QD (single domain) nanosizes.
Competing Interests: The authors declare no competing financial interest.
(© 2022 The Authors. Published by American Chemical Society.)