Standardisation of magnetic NPs

Standardisation of magnetic nanoparticles in liquid suspension.

James Wells, Olga Kazakova, Oliver Posth, Uwe Steinhoff, Sarunas Petronis, Lara K Bogart, Paul Southern, Quentin Pankhurst and Christer Johansson

J. Appl. Phys. D 50, 383003 (2017)

Results of the NanoMag European FP7 project that aims to standardize, improve and redefine analysis methods for magnetic nanoparticles.

Drug releasing nanoplatforms activated by alternating magnetic fields: Review

Drug releasing nanoplatforms activated by alternating magnetic fields.
Damien Mertz, Olivier Sandre, Sylvie Bégin-Colin
Biochimica et Biophysica Acta 1861, 1617 (2017)

Tuning EB by control of interface coupling

Tuning the coercivity and exchange bias by controlling the interface coupling in bimagnetic core/shell nanoparticles.
Gabriel C. Lavorato, Enio Lima, Jr., Horacio E. Troiani, Roberto D. Zysler and Elin L. Winkler
Nanoscale 9, 10240 (2017)

Magneto-thermal capabilities of NP Review

Recent advances of magneto-thermal capabilities of nanoparticles: From design principles to biomedical applications.

Seung-hyun Noh, Seung Ho Moon, Tae-Hyun Shin, Yongjun Lim, Jinwoo Cheon
Nano Today 13, 61 (2017)

Direct Observation of Interactions between Nanoparticles and Nanoparticle Self-Assembly in Solution

Direct Observation of Interactions between Nanoparticles and Nanoparticle Self-Assembly in Solution.
Shu Fen Tan, See Wee Chee, Guanhua Lin, and Utkur MirsaidovAcc. Chem. Res., 50, 1303 (2017)

Influence of atomic lattice order on crystallinity of NP and their properties when a assembled

Impact of the Metallic Crystalline Structure on the Properties of Nanocrystals and Their Mesoscopic Assemblies.
Marie-Paule Pileni
Accounts of Chemical Research ASAP (2017)

The relation between structural atomic lattice and the degree of crystallinity of NP is nicely demonstrated here. Moreover, properties (mechanical, growth processes) of supracrystals also change with the nanocrystallinity of the nanoparticles used as building blocks.

Surface spin canting probed by EELS

Surface spin canting in Fe3O4 and CoFe2O4 NP probed by high-resolution electron energy loss spectroscopy.

D. S. Negi, H. Sharona, U. Bhat, S. Palchoudhury, A. Gupta, and R. Datta
Phys. Rev. B 95, 174444 (2017)

Experimental L3 spectra of CFO recorded (a) and (c) at room temperature and (b) and (d) at liquid nitrogen temperature (77 K) for Fe and Co atoms, respectively. The spectra from core and edge of nanoparticles are colored with green and red, respectively. Dominating features from Td and Oh atomic sites are marked. Kindly note the fine features are only sharper for Co atoms, but not for Fe atoms, suggesting possible formation of uniformly oriented spin canting configuration for Fe atoms but core-shell morphology for Co atoms.

Equilibrium magnetization and magnetization relaxation of multicore magnetic nanoparticles

Equilibrium magnetization and magnetization relaxation of multicore magnetic nanoparticles.
Patrick Ilg
Phys. Rev. B 95, 214427 (2017)

Left: Visualization of a dense random cluster containing $N=100$ nanoparticles prepared as described in Sec. 3a. Right: Visualization of a cluster containing $N=100$ nanoparticles prepared by DLCA with $Q_{\mathrm{dd}}=2$ and $\varepsilon =4$ as described in Sec. 3b.

Surface design of magnetic nanoparticles for stimuli-responsive cancer imaging and therapy

Surface design of magnetic nanoparticles for stimuli-responsive cancer imaging and therapy
Taegyu Kang, Fangyuan Li, Seungmin Baik, Wei Shao, Daishun Ling, Taeghwan Hyeon
Biomaterials 136, 98 (2017)

Thermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen - ACS Nano (ACS Publications)

Thermal Decomposition Synthesis of Iron Oxide Nanoparticles with Diminished Magnetic Dead Layer by Controlled Addition of Oxygen.

Mythreyi Unni,Amanda M. Uhl, Shehaab Savliwala, Benjamin H. Savitzky, Rohan Dhavalikar, Nicolas Garraud, David P Arnold, Lena F. Kourkoutis, Jennifer S. Andrew, and Carlos Rinaldi

ACS Nano 11, 2284 (2017)

Decades of research focused on size and shape control of iron oxide nanoparticles have led to methods of synthesis that afford excellent control over physical size and shape but comparatively poor control over magnetic properties. Popular synthesis methods based on thermal decomposition of organometallic precursors in the absence of oxygen have yielded particles with mixed iron oxide phases, crystal defects, and poorer than expected magnetic properties, including the existence of a thick “magnetically dead layer” experimentally evidenced by a magnetic diameter significantly smaller than the physical diameter. Here, we show how single-crystalline iron oxide nanoparticles with few defects and similar physical and magetic diameter distributions can be obtained by introducing molecular oxygen as one of the reactive species in the thermal decomposition synthesis. This is achieved without the need for any postsynthesis oxidation or thermal annealing. These results address a significant challenge in the synthesis of nanoparticles with predictable magnetic properties and could lead to advances in applications of magnetic nanoparticles.

Standardizing Size- and Shape-Controlled Synthesis of Monodisperse Magnetite (Fe3O4) Nanocrystals by Identifying and Exploiting Effects of Organic Impurities

Standardizing Size- and Shape-Controlled Synthesis of Monodisperse Magnetite Nanocrystals by Identifying and Exploiting Effects of Organic Impurities.

Liang Qiao, Zheng Fu, Ji Li, John Ghosen, Ming Zeng, John Stebbins, Paras N. Prasad, and Mark T. Swihart

ACS Nano 11, 6370 (2017)

Size-Dependent Heating of Magnetic Iron Oxide NP

Size-Dependent Heating of Magnetic Iron Oxide Nanoparticles.
Sheng Tong, Christopher A. Quinto, Linlin Zhang, Priya Mohindra, and Gang Bao

ACS Nano 11, 6808 (2017)

Effect of volume distribution broadenig in properties of NPs

Magnetic properties of nanoparticle compacts with controlled broadening of the particle size distribution.

M. S. Andersson, R. Mathieu, P. S. Normile, S. S. Lee, G. Singh, P. Nordblad, and J. A. De Toro

Phys. Rev. B 95, 184431 (2017)

(a) Low-field (800 A/m) ZFC/FC M/H vs $T$ curves for MIX0 and a diluted sample from the same nanoparticle batch (reference MIX0). M/H values are normalized to the maximum of their ZFC M/H curves. (b) In-phase (${\chi }^{\prime }$) and (c) out-of-phase (${\chi }^{\text{'}\text{'}}$) components of the ac susceptibility as a function of the temperature ($f=10$ Hz) for selected compacts as in the legend in (c). Inset in (b): Temperature of the maximum of the in-phase susceptibility ($T_{\max }$) as a function of the concentration of 11.5-nm particles.

Magnetic properties of large Co clusters

Structural and magnetic properties of large cobalt clusters.
Jaime Souto-Casares, Masahiro Sakurai, and James R. Chelikowsky
Phys. Rev. B 93, 174418 (2016)

Local magnetic moment per atom with respect to the coordination number. Error bars represent the minimum and maximum value. Each set of points has been fitted to a line. A miniature of the specific cluster is shown, with the color map representing the individual local magnetic moment growing in the upper direction.

Surface vacancy mediated pinning in maghemite NP

Surface vacancy mediated pinning of the magnetization in γ−Fe2O3 nanoparticles: A micromagnetic simulation study

Bassel Alkadour, J. I. Mercer, J. P. Whitehead, J. van Lierop, and B. W. Southern

Phys. Rev. B 93, 140411(R) (2016)

The energy landscape for a nanoparticle selected at random from the K10 enemble. Each point on the surface of the sphere represents the energy associated with the alignment of the magnetic moment. The energy is calculated using a mean field approximation based on the distribution of surface vacancies and the average angular distribution of the energy per spins at T=0 shown in Fig. 4. The energy scale associated with the color map shown on the right is given in K.

Competition between interactions and anisotropy in NPs

Understanding particle size and distance driven competition of interparticle interactions and effective single-particle anisotropy.

B Pacakova, A Mantlikova, D Niznansky, S Kubickova and J Vejpravova

Journal of Physics: Condensed Matter 28, 206004 (2016)

 Comparison of volume dependence of TMAX, representing the blocking temperature of the ensemble of the NPs with size distribution and interparticle interactions;  attributed to blocking temperature of Vm affected by interparticle interactions and finally , which is the blocking temperature attributed to Vm after decoupling the effect of dipole–dipole interactions and external DC magnetic field  mT (equation (4)). . Line corresponds to the fit encountering the finite size effect with  Jm−3,  Jm−2.

Particle size-dependent superspin glass behavior in random compacts of monodisperse maghemite nanoparticles - IOPscience

Particle size-dependent superspin glass behavior in random compacts of monodisperse maghemite nanoparticles.
Mikael Svante Andersson, Roland Mathieu, Peter S Normile, Su Seong Lee, Gurvinder Singh, Per Nordblad and Jose Angel De Toro
Materials Research Express 3, 045015 (2016)

 Temperature-dependent (normalized to the maximum of near the onset of dissipation) data replotted as a function of reduced temperature , where the denominator is the temperature of maximum slope of for each sample (h = 80 A m⁻¹, f = 10 Hz).

Mean-field and linear regime approach to magnetic hyperthermia of core–shell nanoparticles: can tiny nanostructures fight cancer? - Nanoscale (RSC Publishing)

Mean-field and linear regime approach to magnetic hyperthermia of core–shell nanoparticles: can tiny nanostructures fight cancer?
Marcus S. Carriao and Andris F. Bakuzis
Nanoscale 8, 8363 (2016)

The phenomenon of heat dissipation by magnetic materials interacting with an alternating magnetic field, known as magnetic hyperthermia, is an emergent and promising therapy for many diseases, mainly cancer. Here, a magnetic hyperthermia model for core–shell nanoparticles is developed. The theoretical calculation, different from previous models, highlights the importance of heterogeneity by identifying the role of surface and core spins on nanoparticle heat generation. We found that the most efficient nanoparticles should be obtained by selecting materials to reduce the surface to core damping factor ratio, increasing the interface exchange parameter and tuning the surface to core anisotropy ratio for each material combination. From our results we propose a novel heat-based hyperthermia strategy with the focus on improving the heating efficiency of small sized nanoparticles instead of larger ones. This approach might have important implications for cancer treatment and could help improving clinical efficacy.

 

Duality of Iron Oxide Nanoparticles in Cancer Therapy: Amplification of Heating Efficiency by Magnetic Hyperthermia and Photothermal Bimodal Treatment - ACS Nano (ACS Publications)

Duality of Iron Oxide Nanoparticles in Cancer Therapy: Amplification of Heating Efficiency by Magnetic Hyperthermia and Photothermal Bimodal Treatment.
Ana Espinosa, Riccardo Di Corato, Jelena Kolosnjaj-Tabi, Patrice Flaud, Teresa Pellegrino, and Claire Wilhelm
ACS Nano 10 2436 (2016)

NP for Cancer diagnosis and treatment: Review

Magnetite nanoparticles for cancer diagnosis, treatment, and treatment monitoring: recent advances.

Richard A. Revia, 

Miqin Zhang

Materials Today 19, 157 (2016)