Predictions of optimal heating by magnetic reversal behavior of magnetic nanowires (MNWs) with different materials

Abstract

Objective

Magnetic nanowires (MNWs) are potential candidates for heating in biomedical applications that require rapid and uniform heating rates, such as warming cryopreserved organs and hyperthermia treatment of cancer cells. Therefore, it is essential to determine which materials and geometries will provide the optimal heating using available alternating magnetic fields (AMF).

Method

Micromagnetic simulations are used to investigate the heating ability of MNWs by predicting their hysteretic behavior. MNWs composed of iron (Fe), nickel (Ni), cobalt (Co) or permalloy (FeNi alloy, Py) with different diameters (10-200 nm) are simulated using object oriented micromagnetic framework (OOMMF).

Results

Hysteresis loops are obtained for each simulated MNW, and the 2D/3D magnetic moment map is simulated to show the reversal mechanism. The heating ability, in terms of specific loss power (SLP), is calculated from the area of the hysteresis loop times frequency for each MNW for comparison with others.

Conclusion

It is estimated that a theoretical optimal heating ability of 2730 W/g can be provided by isolated Co MNWs with 50 nm diameters using a typical AMF system that can supply 72 kA/m field amplitude and 50 kHz in frequency. Generalized correlation between coercivity and size/material of MNWs is provided as a guidance for researchers to choose the most appropriate MNW as a heater for their AMF system and vice versa.

Keywords:

• Magnetic nanowires
• micromagnetic simulation
• nanowarming
• modeling (i.e.
• heat transfer
• ultrasound
• EM
• integrated
• treatment planning)

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are openly available in Figshare at https://doi.org/10.6084/m9.figshare.22040795.v1.

Additional information

Funding

Partial support was provided by the ATP-Bio Engineering Research Center via NSF Award No. EEC-1941543 and the Air Force Office of Scientific Research Dr Ali Sayir via FA9550-21-1-0273. Part of the research was done in the UMN Characterization Facilities and the Minnesota Nanofabrication Center, both with partial support from NSF via MRSEC DMR-2011401 and NSF NNCI ECCS-2025124, and the Institute of Rock Magnetism (NSF EAR-1642268).