Article
Chemistry, Multidisciplinary
A. Omelyanchik, S. Villa, M. Vasilakaki, G. Singh, A. M. Ferretti, A. Ponti, F. Canepa, G. Margaris, K. N. Trohidou, D. Peddis
Summary: By designing nanoparticle systems with core/shell morphology, magnetic anisotropy was successfully modulated, leading to adjustments in magnetic dipolar interactions between particles. Both nanoparticle systems exhibit high saturation magnetisation and display superparamagnetic behavior at room temperature, with strong exchange coupling observed at the core/shell interface.
NANOSCALE ADVANCES
(2021)
Article
Chemistry, Multidisciplinary
Juan A. Ramos-Guivar, Carlo A. Tamanaha-Vegas, Fred Jochen Litterst, Edson C. Passamani
Summary: Ferromagnetic nanostructures were studied using atomistic simulations with Monte Carlo and Landau-Lifshitz-Gilbert methods. The influence of particle size, shape, and interfacial magnetic exchange on the magnetization and magnetic hysteresis behavior was analyzed, showing that finite-size effects play a role in the Curie temperature dependence of the nanoparticles. Adjusting the core size in the Co@Gd core-shell structure allowed for control of the critical temperature, with different interfacial exchange energies leading to varied coercive field values.
Article
Nanoscience & Nanotechnology
Jeotikanta Mohapatra, Meiying Xing, Rui Wu, Jinbo Yang, Ping Liu
Summary: This report investigates the exchange-bias effect of Co/CoO core/shell nanoparticles with an amorphous CoO shell. The spin-glass state in the CoO shell at low temperatures creates a unidirectional anisotropy in the Co core, resulting in a large exchange bias field of up to 3.6 kOe. By improving the crystallinity of the CoO shell, the spin-glass ordering is suppressed, leading to a significantly lower exchange-bias field (2.2 kOe) and a prominent training effect due to multiple easy axes in the multi-crystalline CoO shell. Theoretical studies confirm the significant impact of the emerging spin-glass state on the exchange bias of the system. These findings offer a new approach for manipulating and fine-tuning exchange bias effects in nanoscale systems for spintronics applications.
SCRIPTA MATERIALIA
(2023)
Article
Biochemistry & Molecular Biology
Venkatesha Narayanaswamy, Jayalakshmi Jagal, Hafsa Khurshid, Imaddin A. A. Al-Omari, Mohamed Haider, Alexander S. S. Kamzin, Ihab M. M. Obaidat, Bashar Issa
Summary: Magnetically soft-soft MnFe2O4-Fe3O4 core-shell nanoparticles were synthesized and their magnetic and thermal properties were studied. The results showed that the shell thickness had no significant effect on the magnetic properties, while the interface spin freezing between the shell and core played an important role. These nanoparticles have potential applications in cancer treatment.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Multidisciplinary
Beatrice Muzzi, Martin Albino, Michele Petrecca, Claudia Innocenti, Cesar de Julian Fernandez, Giovanni Bertoni, Clara Marquina, Manuel Ricardo Ibarra, Claudio Sangregorio
Summary: In this study, the effect of dual-doping of Fe-(II) with Co-(II) and Ni-(II) on crystal structure and magnetic properties is investigated. The results show that Ni-Co doped iron oxide core@shell nanoparticles with high coercivity and increased antiferromagnetic ordering transition temperature close to room temperature can be obtained.
Article
Multidisciplinary Sciences
S. P. Tsopoe, C. Borgohain, Manoranjan Kar, Shantanu Kumar Panda, J. P. Borah
Summary: The construction of a core@shell nanostructure enables interfacial integration at the nanoscale domain, providing a wide research space for biomedical applications, especially magnetic fluid hyperthermia. The interconnection between the exchange bias effect and magnetic heating efficiency through interface coupling has gained significant attention. In this study, a CoZnFe2O4@Fe3O4 core@shell nanostructure was designed to enhance the heating ability by assembling mixed ferrite Co0.5Zn0.5Fe2O4 and soft magnetic material Fe3O4. Magnetic scrutiny of the core@shell sample revealed a strong interface activity and validation of the exchange bias effect. The heating response of the magnetic nanoparticles to applied magnetic field and frequency was analyzed at three distinct fields, with the core@shell CZF sample exhibiting significantly higher specific loss power compared to bare F and CZ samples. Moreover, a high intrinsic loss parameter was observed for the core@shell sample, indicating its potential as a highly efficient heating agent.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Physical
Mario Avila-Gutierrez, Arthur Moisset, Anh-Tu Ngo, Salvatore Costanzo, Guilhem Simon, Philippe Colomban, Marc Petit, Christophe Petit, Isabelle Lisiecki
Summary: This study compares the magnetic properties of core/shell nanoparticles made of cobalt (Co) and cobalt oxide (CoO), and analyzes the variations in their crystalline structure. It is found that the crystalline structure of the core/shell nanoparticle has a significant impact on interfacial magnetic coupling, resulting in exchange bias in Cohcp/CoO particles. The measured exchange bias field (655 mT) exceeds previous reports for similar nanoparticles, and this enhancement is attributed to the high-quality Co/CoO interface, the disparate magnetic anisotropy between the core (Co hcp) and the shell (CoO), and the optimal ratio between the core and shell.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2023)
Article
Oncology
Rogier van Oossanen, Jeremy Godart, Jeremy M. C. Brown, Alexandra Maier, Jean-Philippe Pignol, Antonia G. Denkova, Kristina Djanashvili, Gerard C. van Rhoon
Summary: This study investigated a new treatment for breast cancer using thermal ablation with radioactive magnetic nanoparticles. Through computer simulations, it was found that the dose profiles of these nanoparticles are similar to commercial radioactive sources already used in the clinic. This indicates that this new treatment is feasible for clinical application.
Article
Materials Science, Multidisciplinary
Natalia Rinaldi-Montes, Pedro Gorria, Antonio B. Fuertes, David Martinez-Blanco, Zakariae Amghouz, Ines Puente-Orench, Luca Olivi, Javier Herrero-Martin, Maria Paz Fernandez-Garcia, Javier Alonso, Manh-Huong Phan, Hariharan Srikanth, Xavi Marti, Jesus A. Blanco
Summary: The surface symmetry breaking of Cr2O3 nanoparticles leads to a weak ferromagnetic signal that persists up to near room temperature. Additionally, the exchange-bias effect observed at low temperatures up to 30K exhibits resistance to thermal disorder.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Venkatesha Narayanaswamy, Imaddin A. Al-Omari, Aleksandr S. Kamzin, Bashar Issa, Ihab M. Obaidat
Summary: Magnetically hard-soft core-shell ferrite nanoparticles were synthesized using an organometallic decomposition method. The magnetic properties and magnetic heating efficiency for magnetic hyperthermia applications were investigated, and it was found that the core-shell structure exhibited superior performance.
Article
Mechanics
A. El Ghazrani, K. Htoutou, S. Harir, L. B. Drissi
Summary: By performing atomistic simulations using the Monte Carlo method, we studied the behavior of the classical Heisenberg model. First, we investigated the magnetic and thermal properties of a core-shell nanosphere model and analyzed the temperature-dependent magnetization, magnetic susceptibility, and phase diagrams for different exchange interactions. The results revealed diverse behaviors in the Neel classification nomenclature. Furthermore, we applied the same method to study the (Fe, Ni) nanostructure using experimental magnetic parameters, and observed a compensation phenomenon consistent with experimental studies.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2023)
Article
Materials Science, Multidisciplinary
Sarah Jenkins, Roy W. Chantrell, Richard F. L. Evans
Summary: Antiferromagnetic materials have the potential for high-speed, high-density spintronic devices, but reliable detection of their state is challenging. Exchange bias can help with this detection. Intermixing at the interfaces between ferromagnetic and antiferromagnetic layers plays a crucial role in determining the spin state and key parameters in exchange-biased systems.
Article
Materials Science, Ceramics
M. S. Nunes, L. M. da Silva, A. S. Carrico, M. A. Morales, J. H. de Araujo
Summary: In this work, CoFe2O4@CoFe2 (core@shell) nanoparticles were synthesized using a simple method without the use of special reagents or gases. Glutaraldehyde crosslinked chitosan beads containing CoFe2O4 nanoparticles were prepared and then subjected to thermal treatment at high temperatures and in vacuum. The thermal treatment released CO gas from chitosan, which helped to reduce Fe3+ and Co2+ to their zero valence state.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Multidisciplinary
Suchandra Goswami, Pushpendra Gupta, Sagarika Nayak, Subhankar Bedanta, Oscar Iglesias, Manashi Chakraborty, Debajyoti De
Summary: This study reports the method of controlling the exchange bias effect by manipulating the interparticle interactions in nanocrystalline core/shell structures. The results indicate that the interparticle interactions have a significant impact on the magnetic properties, with a more pronounced collective behavior observed in concentrated assemblies. This finding contributes to a better understanding of the magnetic behavior in nanoparticle systems.
Article
Biochemistry & Molecular Biology
Javier Garcia, Ruth Gutierrez, Ana S. Gonzalez, Ana I. Jimenez-Ramirez, Yolanda Alvarez, Victor Vega, Heiko Reith, Karin Leistner, Carlos Luna, Kornelius Nielsch, Victor M. Prida
Summary: Tuning and controlling the magnetic properties of nanomaterials is crucial for implementing new technologies. In this study, core/shell Ni@(NiO, Ni(OH)2) nanowire arrays were fabricated using an electrochemical approach, and their magnetic properties were characterized. The results showed surface oxidation-induced magnetic hardening in the nanowires and an increasing exchange bias effect at low temperatures.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Materials Science, Multidisciplinary
Marianna Vasilakaki, Ioulia Chikina, Valeri B. Shikin, Nikolaos Ntallis, Davide Peddis, Andrey A. Varlamov, Kalliopi N. Trohidou
APPLIED MATERIALS TODAY
(2020)
Article
Materials Science, Multidisciplinary
Marianna Vasilakaki, Fevronia Gemenetzi, Eamonn Devlin, Dong Kee Yi, Siti Nurhanna Riduan, Su Seong Lee, Jackie Y. Ying, Georgia C. Papaefthymiou, Kalliopi N. Trohidou
Summary: The effect of core size on the magnetic behavior of nanoparticle assemblies was investigated, showing that an increase in magnetic core size results in a shift of the maximum magnetization peak to higher temperatures. The study sheds light on how interparticle distance and magnetic core size influence the behavior of the assembly.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Multidisciplinary Sciences
D. Peddis, K. N. Trohidou, M. Vasilakaki, G. Margaris, M. Bellusci, F. Varsano, M. Hudl, N. Yaacoub, D. Fiorani, P. Nordblad, R. Mathieu
Summary: The non-equilibrium dynamics of the superspin glass state in a dense assembly of about 2 nm MnFe2O4 nanoparticles was studied and found to exhibit glassy magnetic features similar to atomic spin glasses. However, some differences were observed, indicating the non-atomic nature of the superspin glass.
SCIENTIFIC REPORTS
(2021)
Review
Chemistry, Multidisciplinary
Maryam Abdolrahimi, Marianna Vasilakaki, Sawssen Slimani, Nikolaos Ntallis, Gaspare Varvaro, Sara Laureti, Carlo Meneghini, Kalliopi N. Trohidou, Dino Fiorani, Davide Peddis
Summary: This work provides a critical overview of the effects of organic coating on the magnetic properties of nanoparticles, demonstrating the significant impact of surface structure modification and assembly morphology control on magnetic properties.
Article
Chemistry, Multidisciplinary
George Antonaropoulos, Marianna Vasilakaki, Kalliopi N. Trohidou, Vincenzo Iannotti, Giovanni Ausanio, Milinda Abeykoon, Emil S. Bozin, Alexandros Lappas
Summary: The incorporation of cobalt and atomic-scale defects in iron oxide nanocrystals has been shown to enhance their magnetic properties, with Monte Carlo simulations revealing an increase in magnetocrystalline anisotropy due to a low content of Co ions in the lattice. The specific absorption rate (SAR) calculations demonstrate that the protection of the rock salt core and preservation of the heterostructure play a key role in magnetically mediated heating efficacies for potential use in magnetic hyperthermia applications.
Article
Chemistry, Multidisciplinary
Elena H. Sanchez, Marianna Vasilakaki, Su Seong Lee, Peter S. Normile, Mikael S. Andersson, Roland Mathieu, Alberto Lopez-Ortega, Benoit P. Pichon, Davide Peddis, Chris Binns, Per Nordblad, Kalliopi Trohidou, Josep Nogues, Jose A. De Toro
Summary: Dense systems of magnetic nanoparticles can exhibit collective behavior, and it remains unclear whether the transition temperature is influenced by particle anisotropy or determined by interparticle dipolar interactions. Additionally, the minimum ratio of dipole-dipole interaction to nanoparticle anisotropy energies necessary for the crossover from individual to collective behavior is unknown. This study investigates particle assemblies with varying anisotropy and finds a threshold value to suppress collective behavior. The findings have practical applications in predicting the behavior of interacting particle assemblies.
Article
Chemistry, Multidisciplinary
Marianna Vasilakaki, Nikolaos Ntallis, Dino Fiorani, Davide Peddis, Kalliopi N. Trohidou
Summary: This study systematically investigates the effect of albumin coating on the magnetic behavior of ultra-small MnFe2O4 nanoparticles and compares it with that of pure Mn ferrite nanoparticle dense assembly. The experimental findings are well reproduced by numerical simulations. The results provide evidence that the interplay between intra-particle and intra-cluster exchange interactions strongly influences the exchange bias and coercive field values, with dipolar interactions playing a minor role. Furthermore, the albumin coating does not affect the thermal stability of the observed superspin glass phase.
NANOSCALE ADVANCES
(2022)
Article
Chemistry, Multidisciplinary
Franciscarlos Gomes da Silva, Marianna Vasilakaki, Rafael Cabreira Gomes, Renata Aquino, Alex Fabiano Cortez Campos, Emmanuelle Dubois, Regine Perzynski, Jerome Depeyrot, Kalliopi Trohidou
Summary: A mesoscopic scale approach and the Monte Carlo method were used to study the exchange bias behaviour of nanoparticles with different compositions. The results showed that the exchange bias in the hard/soft sample mainly comes from the intraparticle core/shell structure, while the interplay between internal characteristics and interparticle interactions is more important in the soft/soft sample. In the diluted frozen ferrofluid sample, the exchange bias effects are reduced and primarily come from the intra particle structure.
NANOSCALE ADVANCES
(2022)
Article
Chemistry, Multidisciplinary
A. Omelyanchik, S. Villa, M. Vasilakaki, G. Singh, A. M. Ferretti, A. Ponti, F. Canepa, G. Margaris, K. N. Trohidou, D. Peddis
Summary: By designing nanoparticle systems with core/shell morphology, magnetic anisotropy was successfully modulated, leading to adjustments in magnetic dipolar interactions between particles. Both nanoparticle systems exhibit high saturation magnetisation and display superparamagnetic behavior at room temperature, with strong exchange coupling observed at the core/shell interface.
NANOSCALE ADVANCES
(2021)