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
J. K. Han, A. A. Baker, J. R. I. Lee, S. K. McCall
Summary: Exchange coupling in a model core-shell system is demonstrated as a step towards 3D exchange spring magnets. High-quality core-shell nanoparticles of Ni@CoFe2O4 were fabricated using a simple two-step method. The microstructural quality was validated using TEM, confirming a well-defined interface between the core and the shell. Results showed a strongly temperature-dependent two-phase magnetic hysteresis loop, indicating a coupling of approximately 50% between the core and the shell. Element-specific XMCD hysteresis confirmed the presence of exchange coupling, suppressing the superparamagnetism of the Ni core at room temperature, and achieving a coercivity of >6 kOe at 80 K. These findings provide a pathway for the development of heterostructured metal-oxide exchange-coupled nanoparticles with improved maximum energy product.
Article
Chemistry, Physical
J. Xavier, R. B. da Silva, J. C. R. Araujo, C. A. M. Iglesias, E. D. Silva Filho, J. L. C. Fonseca, J. M. Soares, P. B. Souza, C. C. Pla Cid, M. Gamino, S. N. de Medeiros, M. A. Correa, F. Bohn
Summary: The CoFe2O4@BiFeO3 core/shell nanoparticles were synthesized using coprecipitation, with structural, morphological, and magnetic properties thoroughly investigated. The study revealed a core/shell nanostructure with pure phases, magnetic response characteristics, and spin glass behavior in the nanoparticles, demonstrating the feasibility of the coprecipitation and calcination processes for producing high-quality core/shell nanostructures.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
J. Mohapatra, J. Elkins, M. Xing, D. Guragain, Sanjay R. Mishra, J. Ping Liu
Summary: Self-assembly of nanoparticles can lead to the formation of new materials with desired physical properties. In this study, composition-modulated bimagnetic nanoparticles were used to produce ordered structures with enhanced magnetic properties, such as anisotropy and remanent magnetization. The presence of magnetic fields during assembly played a key role in the formation of oriented nanoparticle chains in superlattice structures.
Article
Chemistry, Multidisciplinary
Hiroshi Sugimoto, Tatsuki Hinamoto, Yusuke Kazuoka, Artyom Assadillayev, Soren Raza, Minoru Fujii
Summary: The optical resonances of a core-shell nanosphere with a high refractive index core have been investigated in this study. The scattering and absorption spectra of the core-shell nanosphere were analyzed, revealing a transition of the hybridization scheme around a refractive index of approximately 2. Single particle scattering spectroscopy and electron energy loss spectroscopy were used to study the resonance modes of the core-shell nanosphere, showing different hybridized modes depending on the core diameter.
Article
Chemistry, Multidisciplinary
Namsoon Eom, Maria E. Messing, Jonas Johansson, Knut Deppert
Summary: The study examines the core-shell preference of bimetallic nanoparticles and the impact of surface segregation phenomena. It reveals that cohesive energy and Wigner-Seitz radius are the primary factors influencing the core-shell preference and level of segregation in these nanoparticles.
Article
Chemistry, Multidisciplinary
Jingjie Ge, Riccardo Ruixi Chen, Xiao Ren, Jiawei Liu, Samuel Jun Hoong Ong, Zhichuan J. Xu
Summary: The rational design of FM-AFM core-shell catalysts enhances electron transport efficiency and improves OER activity, with critical factors including shell thickness and magnetic domain structure.
ADVANCED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Yu. V. Knyazev, D. A. Balaev, S. A. Skorobogatov, D. A. Velikanov, O. A. Bayukov, S. V. Stolyar, R. N. Yaroslavtsev, R. S. Iskhakov
Summary: The spin dynamics of interacting and weakly interacting magnetic ultrasmall ferrihydrite nanoparticles were studied. The magnetic susceptibilities of the samples were measured and it was found that the interactions between nanoparticles induce the formation of a cluster spin-glass state below the superparamagnetic blocking temperature. The coating of nanoparticles increases the critical scaling index and slows down the dynamics of correlated spins.
Article
Environmental Sciences
Sultan Alomairy, Lalitha Gnanasekaran, Saravanan Rajendran, Walaa F. Alsanie
Summary: This study focuses on the application of cinnamon biochar as an active anti-oxidant agent in the titania-cobalt ferrite nanocore-shell structure for wastewater treatment. The results show that the Biochar/TiO2/CoFe2O4 composite exhibits high degradation efficiency against chlorophenol pollutants under visible light, due to its porous structure and charge separation capability. The recyclability and stability of the composite make it a promising candidate for biofuel generation and energy storage devices.
ENVIRONMENTAL RESEARCH
(2023)
Article
Chemistry, Physical
Sofia Nieves Casillas-Popova, Jesus A. Arenas-Alatorre, Pandiyan Thangarasu, Gustavo Tavizon, Maria Josefa Bernad-Bernad, Jesus Gracia-Mora
Summary: The current research focuses on the synthesis of a non-magnetic shell layer on a magnetic core CoFe2O4-X (X = BaTiO3 or Bi4Ti3O12) using a two-step wet chemical method. Various techniques were used to characterize the synthesized samples, and the results showed that the nature of the shell influenced the core-shell formation and magnetic properties.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Chemistry, Multidisciplinary
Jeongeon Kim, Xenia Medvedeva, Jury J. Medvedev, Cheongwon Bae, Juyeong Kim, Anna Klinkova
Summary: Understanding the relationship between structure and performance in nanoscale electrocatalysts for urea electrolysis is important for efficient waste treatment and hydrogen production or CO2 reduction. We investigate the role of lattice strain in Pd-Ni core-shell nanocubes on the dominance of the urea overoxidation pathway.
Article
Materials Science, Ceramics
Fatma Unal, Cansu Tasar, Batur Ercan
Summary: By synthesizing antibacterial magneto-luminescent 58S bioactive glasses, which possess magnetic and luminescent properties, this study showed that they can effectively target and localize at the infection foci without dispersing into the body. The Eu doped SPION/Bioactive glass nanoparticles exhibited increased osteoblast viability and inhibited bacterial growth, while possessing superparamagnetic properties and exhibiting red luminescence.
CERAMICS INTERNATIONAL
(2023)
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
Nanoscience & Nanotechnology
Sai Chen, Yuchuan Cheng, Zihui Zhao, Ke Zhang, Tingting Hao, Yi Sui, Wen Wang, Jiupeng Zhao, Yao Li
Summary: In this study, barium titanate@nanocarbon shell (BTO@NCs) composites were prepared by introducing carbonized polydopamine (C-PDA) into the shell, effectively controlling the shell thickness, surface polar functional groups, and sp(2)/sp(3) hybridized carbon content. The maximum yield stress of BTO@NCs-24 h ER fluid reached 2.5 kPa under an electric field of 4 kV mm(-1) due to the increased content of sp(3) C-OH and oxygenous functional groups within the shell, resulting in a rapidly achievable polarization. Additionally, SiO2@NCs and TiO2@NCs ER fluids were also prepared, confirming the approach to high-performance ER fluids based on nanocarbon composites.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Munawar Khalil, Alwy Fahmi, Noverra Mardhatillah Nizardo, Zulhelmi Amir, Badrul Mohamed Jan
Summary: The study successfully investigated the application of thermosensitive core-shell Fe3O4@PNIPAM nanogels in enhanced oil recovery. The nanogels exhibited high viscosity and low nanofluid mobility ratio at high temperatures, leading to efficient displacement front during EOR. Additional oil recovery of about 25.75% was achieved when the nanofluid was injected at a temperature of 45 degrees C, although a further increase in temperature could result in reduced oil recovery due to nanogel precipitation.
