Determining effective magnetic moment of multicore nanoparticles

June 16, 2020

WASHINGTON, June 16, 2020 -- Magnetic nanoparticles, a class of nanoparticles that can be manipulated by magnetic fields, have a wide range of technical and biomedical applications, including magnetic hyperthermia, targeted drug delivery, new magnetic storage media and nanorobots. Most commercial nanoparticles do not possess a single magnetic core but have a number of small magnetic crystals called crystallites.

The important question for researchers is how these crystallites behave inside a multicore nanoparticle and how they respond to an applied magnetic field. A paper in the Journal of Applied Physics, from AIP Publishing, compares the effective magnetic moments of different multicore nanoparticle systems and shows that they are magnetic-field dependent.

"The effective magnetic moment of such a multicore nanoparticle depends on various parameters, such as the size of magnetic crystallites, their packing density, core configuration and the magnetic interaction between them," said Frank Ludwig, one of the authors of the paper.

Many experimental findings indicate that the ensemble of crystallites behaves like a single magnetic core with some effective magnetic moment. Research has been directed toward determining how this effective magnetic moment is related to the number and size of crystallites inside one multicore nanoparticle because many applications require a large magnetic moment, which, e.g., determines the strength of the magnetic force needed for their manipulation.

The paper's findings are important for researchers optimizing magnetic nanoparticles for various applications, including magnetic hyperthermia and magnetic drug targeting, two new frontiers in cancer therapy.

In magnetic hyperthermia, the nanoparticles are located at the tumor cells. A magnetic field with a frequency and amplitude that will heat the nanoparticles to a temperature of approximately 42-44 degrees Celsius is applied, which kills the tumor cells.

In magnetic drug targeting, the capsule with drugs and magnetic particles is directed to the tumor by magnetic field gradients. When they arrive at the tumor, the drugs are released from the capsule by various techniques. Targeted drug therapy can result in dramatic reduction of doses and side effects versus traditional chemotherapy.

Technical applications of nanoparticles range from new magnetic storage media to nanorobots. Storage media made of nanoparticles are much smaller than existing media and can store greater amounts of data. Nanorobots are machines that can build and manipulate things precisely at an atomic level and can be used in a wide variety of contexts such as miniscule sensors that monitor blood chemistry.

Ludwig said continuing to gain a better understanding of the effective magnetic moment of multicore nanoparticles and, especially, its field dependence is essential for both basic science and applications.
The article, "Magnetic field dependence of the effective magnetic moment of multi-core nanoparticles," is authored by Tamara Kahmann and Frank Ludwig. The article will appear in the Journal of Applied Physics on June 16, 2020 (DOI: 10.1063/5.0011629). After that date, it can be accessed at


The Journal of Applied Physics is an influential international journal publishing significant new experimental and theoretical results in all areas of applied physics. See

American Institute of Physics

Related Nanoparticles Articles from Brightsurf:

How to get more cancer-fighting nanoparticles to where they are needed
University of Toronto Engineering researchers have discovered a dose threshold that greatly increases the delivery of cancer-fighting drugs into a tumour.

Nanoparticles: Acidic alert
Researchers of Ludwig-Maximilians-Universitaet (LMU) in Munich have synthesized nanoparticles that can be induced by a change in pH to release a deadly dose of ionized iron within cells.

3D reconstructions of individual nanoparticles
Want to find out how to design and build materials atom by atom?

Directing nanoparticles straight to tumors
Modern anticancer therapies aim to attack tumor cells while sparing healthy tissue.

Sweet nanoparticles trick kidney
Researchers engineer tiny particles with sugar molecules to prevent side effect in cancer therapy.

A megalibrary of nanoparticles
Using straightforward chemistry and a mix-and-match, modular strategy, researchers have developed a simple approach that could produce over 65,000 different types of complex nanoparticles.

Dialing up the heat on nanoparticles
Rapid progress in the field of metallic nanotechnology is sparking a science revolution that is likely to impact all areas of society, according to professor of physics Ventsislav Valev and his team at the University of Bath in the UK.

Illuminating the world of nanoparticles
Scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) have developed a light-based device that can act as a biosensor, detecting biological substances in materials; for example, harmful pathogens in food samples.

What happens to gold nanoparticles in cells?
Gold nanoparticles, which are supposed to be stable in biological environments, can be degraded inside cells.

Lighting up cardiovascular problems using nanoparticles
A new nanoparticle innovation that detects unstable calcifications that can trigger heart attacks and strokes may allow doctors to pinpoint when plaque on the walls of blood vessels becomes dangerous.

Read More: Nanoparticles News and Nanoparticles Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to