Technologically relevant magnetic nanoparticles for biomedicine are rarely noninteracting single-domain nanoparticles; instead, they are often interacting, with complex physical and magnetic structures. In this paper, we present both experimental and simulated magnetic hysteresis loops of a system of magnetic nanoparticles with significant interparticle interactions and a well-defined intraparticle structure which are used for magnetic nanoparticle hyperthermia cancer treatment. Experimental measurements were made at 11 K on suspensions of magnetic nanoparticles dispersed in HO which have been frozen in a range of applied magnetic fields to tune the interparticle interactions. Micromagnetic simulations of hysteresis loops investigated the roles of particle orientation with respect to the field and of particle chaining in the shape of the hysteresis loops. In addition, we present an analysis of the magnetic anisotropy arising from the combination of magnetocrystalline and shape anisotropy, given the well-defined internal structure of the nanoparticles. We find that the shape of the experimental hysteresis loops can be explained by the internal magnetic structure, modified by the effects of interparticle interactions from chaining.
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J Phys Chem B
January 2025
Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
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December 2024
Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA; High Meadows Environmental Institute, Princeton University, Princeton, NJ 08544, USA. Electronic address:
Knowledge Gap: The aggregation of clay minerals in liquid water exemplifies colloidal self-assembly in nature. These negatively charged aluminosilicate platelets interact through multiple mechanisms with different sensitivities to particle shape, surface charge, aqueous chemistry, and interparticle distance and exhibit complex aggregation structures. Experiments have difficulty resolving the associated colloidal assemblages at the scale of individual particles.
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January 2025
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, United States. Electronic address:
In agricultural and waste management systems, dairy manure wastewater is often recycled for irrigation. However, a key challenge lies in handling suspended solids (SS) and effectively dewatering sludge. To address this, an innovative polycationic soybean protein-based flocculant (SPI+) was developed and applied to enhance flocculation and sludge dewatering efficiency.
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December 2024
Physikalisches Institut der Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany.
We realize a Laughlin state of two rapidly rotating fermionic atoms in an optical tweezer. By utilizing a single atom and spin resolved imaging technique, we sample the Laughlin wave function thereby revealing its distinctive features, including a vortex distribution in the relative motion, correlations in the particles' relative angle, and suppression of the interparticle interactions. Our Letter lays the foundation for atom-by-atom assembly of fractional quantum Hall states in rotating atomic gases.
View Article and Find Full Text PDFNano Lett
January 2025
College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China.
The net charge of individual nanoparticles in nonpolar solvents plays a critical role in their intrinsic properties like charge carrier lifetime, electron transport, and interparticle interactions. However, there is a long-standing belief that the oil-dispersed nanoparticles inherently possess no net charge. This work presents an approach for directly quantifying the net charge of individual nanoparticles.
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