| Title: |
Exploring the complex interplay of anisotropies in magnetosomes of magnetotactic bacteria |
| Authors: |
Gandia, David, Marcano, Lourdes, Gandarias, Lucía, Gubieda, Alicia G., García-Prieto, Ana, Barquín, Luis Fernández, Espeso, Jose Ignacio, Jefremovas, Elizabeth Martín, Orue, Iñaki, de Cerio, Ana Abad Diaz, Fdez-Gubieda, M. Luisa, Alonso, Javier |
| Publication Year: |
2024 |
| Collection: |
Condensed Matter
Physics (Other) |
| Subject Terms: |
Condensed Matter - Materials Science, Physics - Biological Physics |
| More Details: |
Magnetotactic bacteria (MTB) are of significant interest for biophysical applications, particularly in cancer treatment. The biomineralized magnetosomes produced by these bacteria are high-quality magnetic nanoparticles that form chains through a highly reproducible natural process. Specifically, Magnetovibrio blakemorei and Magnetospirillum gryphiswaldense exhibit distinct magnetosome morphologies: truncated hexa-octahedral and truncated octahedral shapes, respectively. Despite having identical compositions (magnetite, Fe3O4) and comparable dimensions, their effective uniaxial anisotropies differ significantly, with M. blakemorei showing ~25 kJ/m^3 and M. gryphiswaldense ~11 kJ/m^3 at 300K. This variation presents a unique opportunity to explore the role of different anisotropy contributions in the magnetic responses of magnetite-based nanoparticles. This study systematically investigates these responses by examining static magnetization as a function of temperature (M vs. T, 5 mT) and magnetic field (M vs. H, up to 1 T). Above the Verwey transition temperature (110 K), the effective anisotropy is dominated by shape anisotropy, notably increasing coercivity for M. blakemorei by up to two-fold compared to M. gryphiswaldense. Below this temperature, the effective uniaxial anisotropy increases non-monotonically, significantly altering magnetic behavior. Our simulations based on dynamic Stoner-Wohlfarth models indicate that below the Verwey temperature, a uniaxial magnetocrystalline contribution emerges, peaking at ~22-24 kJ/m^3 at 5 K, values close to those of bulk magnetite. This demonstrates the profound impact of anisotropic properties on the magnetic behaviors and applications of magnetite-based nanoparticles and highlights the exceptional utility of magnetosomes as ideal model systems for studying the complex interplay of anisotropies in magnetite-based nanoparticles. |
| Document Type: |
Working Paper |
| Access URL: |
http://arxiv.org/abs/2410.00550 |
| Accession Number: |
edsarx.2410.00550 |
| Database: |
arXiv |
