Generation, Self-assembly, and Characterisation of Medium-entropy Fe0.10Ni0.40Co0.25Pt0.25 Nanoparticles
(2025) FYSM64 20251Department of Physics
Synchrotron Radiation Research
- Abstract
- The ongoing pursuit of advanced multicomponent magnetic nanomaterials with tailored functionalities for applications in data storage, spintronics, and biomedicine necessitates novel synthesis approaches beyond conventional template-based methods. In response, this thesis investigates the generation, self-assembly, and characterisation of largely little-known Fe0.10Ni0.40Co0.25Pt0.25 medium-entropy alloy (MEA). Using spark ablation, a gas-phase technique, Fe0.10Ni0.40Co0.25Pt0.25 MEA nanoparticles were synthesised and subsequently self-assembled into one-dimensional nanochains under an external magnetic field during deposition. Comprehensive crystallographic analysis via scanning electron microscopy, transmission electron microscopy, and... (More)
- The ongoing pursuit of advanced multicomponent magnetic nanomaterials with tailored functionalities for applications in data storage, spintronics, and biomedicine necessitates novel synthesis approaches beyond conventional template-based methods. In response, this thesis investigates the generation, self-assembly, and characterisation of largely little-known Fe0.10Ni0.40Co0.25Pt0.25 medium-entropy alloy (MEA). Using spark ablation, a gas-phase technique, Fe0.10Ni0.40Co0.25Pt0.25 MEA nanoparticles were synthesised and subsequently self-assembled into one-dimensional nanochains under an external magnetic field during deposition. Comprehensive crystallographic analysis via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction confirmed the formation of a predominantly single-crystalline, single-phase, face-centred cubic structure with an experimental lattice parameter of a = 3.6360 ± 0.0002 Å, which is in close agreement with the Vegard’s theorem value of 3.6304 Å for the measured composition. Magnetic characterisation using vibrating-sample magnetometry revealed coercivity values of approximately 24 kA m−1 for nanoparticles and 26 kA m−1 for nanochains, classifying the material as an intermediate magnetic type. Angle-dependent studies demonstrated isotropic magnetic behaviour for the nanoparticles and a major uniaxial magnetic anisotropy, primarily attributed to shape effects, for the nanochains, complemented by a 4-fold symmetry. This presented work on Fe0.10Ni0.40Co0.25Pt0.25 nanostructures paves the way for further exploration of their fundamental properties and potential in advanced technological applications. (Less)
- Popular Abstract
- In materials science, the most fascinating discoveries often emerge at the tiniest scales, revealing a hidden world where materials exhibit astonishing and unexpected behaviours. At those scales, tiny pieces of matter, called nanoparticles, possess unique properties that do not exist in their larger bulk forms. From enhanced strength and novel electrical characteristics to remarkable magnetic behaviours, nanoparticles are reshaping our understanding of what materials can do. Magnetic nanoparticles, in particular, drive innovations in healthcare, energy and sustainability, and data-storage solutions.
The grand vision in this field is not just to create these remarkable particles but to arrange them precisely, much like assembling bricks at... (More) - In materials science, the most fascinating discoveries often emerge at the tiniest scales, revealing a hidden world where materials exhibit astonishing and unexpected behaviours. At those scales, tiny pieces of matter, called nanoparticles, possess unique properties that do not exist in their larger bulk forms. From enhanced strength and novel electrical characteristics to remarkable magnetic behaviours, nanoparticles are reshaping our understanding of what materials can do. Magnetic nanoparticles, in particular, drive innovations in healthcare, energy and sustainability, and data-storage solutions.
The grand vision in this field is not just to create these remarkable particles but to arrange them precisely, much like assembling bricks at the nanoscale. By doing so, we can build new or poorly explored components that not only retain the unique qualities of individual nanoparticles but also gain extraordinary features from their collective interactions. This concept, known as nanoparticle assembly, is central to the research presented in this thesis.
This work explores a sophisticated method for creating and assembling specialised magnetic nanoparticles with enhanced control, focusing on a technique called spark ablation. Imagine controlled, miniature lightning strikes between two metal electrodes: each spark vaporises a tiny amount of material, which then rapidly cools and condenses in a pure-gas environment to form nanoparticles. This gas-phase method is remarkably clean, directly producing particles from bulk metals without hazardous chemical solvents, a significant advantage over many traditional solution-based techniques.
A key benefit of spark ablation is the precise control it offers over particle composition, enabling us to venture into the realm of medium-entropy alloys (MEAs). Rather than simple, single-element particles, we “cook” an atomic cocktail, Fe₀.₁₀Ni₀.₄₀Co₀.₂₅Pt₀.₂₅, blending four ferromagnetic metals and platinum into a novel magnetic material. Furthermore, because the nanoparticles form in a gas stream, they can be directly guided and deposited onto surfaces. By applying a magnetic field during deposition, we encourage their self-assembly into ordered nanochains.
The core of this thesis involves a comprehensive characterisation of these newly synthesized nanostructures. Scanning and transmission electron microscopy reveal particle morphology and chain formation, while X-ray diffraction confirms the intended alloy’s crystalline structure and atomic arrangement. Magnetometry then explores the magnetic properties of both individual nanoparticles and their assembled chains, showing how collective behaviour depends on particle arrangement. This study demonstrates that spark ablation offers a versatile, eco-friendly route to complex alloy nanoparticles and that magnetic-field-assisted assembly can produce ordered nanostructures, paving the way for future investigations into their fundamental properties and potential applications. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9213406
- author
- Herz, Sam Emile LU
- supervisor
- organization
- course
- FYSM64 20251
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Nanomagnetism, FeNiCoPt, Self-assembly
- language
- English
- id
- 9213406
- date added to LUP
- 2025-10-08 08:53:50
- date last changed
- 2025-10-08 08:53:50
@misc{9213406,
abstract = {{The ongoing pursuit of advanced multicomponent magnetic nanomaterials with tailored functionalities for applications in data storage, spintronics, and biomedicine necessitates novel synthesis approaches beyond conventional template-based methods. In response, this thesis investigates the generation, self-assembly, and characterisation of largely little-known Fe0.10Ni0.40Co0.25Pt0.25 medium-entropy alloy (MEA). Using spark ablation, a gas-phase technique, Fe0.10Ni0.40Co0.25Pt0.25 MEA nanoparticles were synthesised and subsequently self-assembled into one-dimensional nanochains under an external magnetic field during deposition. Comprehensive crystallographic analysis via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction confirmed the formation of a predominantly single-crystalline, single-phase, face-centred cubic structure with an experimental lattice parameter of a = 3.6360 ± 0.0002 Å, which is in close agreement with the Vegard’s theorem value of 3.6304 Å for the measured composition. Magnetic characterisation using vibrating-sample magnetometry revealed coercivity values of approximately 24 kA m−1 for nanoparticles and 26 kA m−1 for nanochains, classifying the material as an intermediate magnetic type. Angle-dependent studies demonstrated isotropic magnetic behaviour for the nanoparticles and a major uniaxial magnetic anisotropy, primarily attributed to shape effects, for the nanochains, complemented by a 4-fold symmetry. This presented work on Fe0.10Ni0.40Co0.25Pt0.25 nanostructures paves the way for further exploration of their fundamental properties and potential in advanced technological applications.}},
author = {{Herz, Sam Emile}},
language = {{eng}},
note = {{Student Paper}},
title = {{Generation, Self-assembly, and Characterisation of Medium-entropy Fe0.10Ni0.40Co0.25Pt0.25 Nanoparticles}},
year = {{2025}},
}