Published by the American Institute of Physics. Related ArticlesFe3O4-citrate-curcumin: Promising conjugates for superoxide scavenging, tumor suppression and cancer hyperthermia J. Appl. Phys. 111, 064702 (2012) Integrated intravital microscopy and mathematical modeling to optimize nanotherapeutics delivery to tumors AIP Advances 2, 011208 (2012) In vitro cytotoxicity of Selol-loaded magnetic nanocapsules against neoplastic cell lines under AC magnetic field activation J. Appl. Phys. 111, 07B335 (2012) Magnetically driven spinning nanowires as effective materials for eradicating living cells J. Appl. Phys. 111, 07B329 (2012) Experimental characterization of electrochemical synthesized Fe nanowires for biomedical applications J. Appl. Phys. 111, 056103 (2012) Additional information on J. Appl. Phys. We show both experimental evidences and Monte Carlo modeling of the effects of interparticle dipolar interactions on the hysteresis losses. Results indicate that an increase in the intensity of dipolar interactions produce a decrease in the magnetic susceptibility and hysteresis losses, thus diminishing the hyperthermia output. These findings may have important clinical implications for cancer treatment.

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Molecular spin qubits have been shown to reach sufficiently long quantum coherence times to envision their use as hardware in quantum processors. These will however require their implementation in hybrid solid-state devices for which the controlled localization and homogeneous orientation of the molecular qubits will be necessary. An alternative to isolated molecules that can ensure these key aspects is 2D framework in which the qubit would act as node. In this work, it is demonstrated that the isolated metalloporphyrin [Cu(H 4 TCPP)] molecule is a potential spin qubit, and maintains similar quantum coherence as node in a 2D [{CuTCPP}Zn 2 (H 2 O) 2 ] metal-organic framework. Mono-and multilayer deposits of nanosheets of a similar 2D framework are then successfully formed following a modular method based on Langmuir-Schaefer conditions. The orientation of the {CuTCPP} qubit nodes in these nanosheets is homogeneous parallel to the substrate. These nanosheets are also formed with a control over the qubit concentration, i.e., by dilution with the unmetallated porphyrin. Eventually, 2D nanosheets are formed in situ directly on a substrate, through a simple protocol devised to reproduce the Langmuir-Schaefer conditions locally. Altogether these studies show that 2D spin qubit frameworks are ideal components to develop a hybrid quantum computing architecture. and gates first arose in the form of purely organic systems, using either the multiple nuclear spins of rationally selected molecules or the electronic spin(s) of open shell organic molecules bearing one or multiple radicals. The careful design and selection of such organic molecules coupled to sophisticated experiments have allowed implementing realistic quantum operations using ensembles of these. [2] Paramagnetic coordination complexes were later proposed as alternative molecular spin qubits, after it was argued and shown that the molecule electronic spin orientation and quantum superpositions allow to encode quantum bit (qubit) states. [3] Recent improvements in the coherence times of these molecular spin qubits [4] and the unique ability to design molecules with multiple qubits as prototypes of quantum gates [5] have brought this scheme to a point where it becomes reasonable to envision the design of a magnetic quantum processor. A magnetic molecule has even recently been used to implement Grover's quantum algorithm, albeit using its metal ion nuclear spin. [6] One of the advantages of the molecular scheme is that macroscopic numbers of identical qubits are obtained in one sole reaction. While this is appealing for the daunting challenge of scaling to a usable size, common to all proposed schemes, [7] the technology to build a scalable quantum architecture based on molecular qubits is

The specific absorption rate (SAR) of a maghemite-based ferrofluid, measured at 315 K, 3 kA/m, and 109 kHz, was found to double as the ferrofluid concentration was decreased by a factor of 4. The ferrofluid contained nonagglomerated, highly crystalline, and monodisperse nanoparticles with an average size of 11.6 nm and an initial concentration of 8.14 mg/mL. The magnetic characterization of three different concentrations of this ferrofluid revealed several effects typical of the presence of magnetic interactions, such as the decrease of initial susceptibility values (liquid ferrofluid) and Néel relaxation times, τN (frozen ferrofluid), with increasing concentration. The accurate SAR determination in adiabatic conditions allowed estimating the τN values of the liquid ferrofluid, which displayed the same trend against concentration as those obtained in the frozen state. Such a trend allowed explaining qualitatively the degradation of the heating performance of the ferrofluid upon increasing concentration. Eventually, correlation between τN values in both states was discussed in terms of several theoretical models described in the literature and developed to explain the properties of an assembly of nanoparticles with dipolar interactions.

One current challenge of magnetic hyperthermia is achieving therapeutic effects with a minimal amount of nanoparticles, for which improved heating abilities are continuously pursued. However, it is demonstrated here that the performance of magnetite nanocubes in a colloidal solution is reduced by 84% when they are densely packed in three-dimensional arrangements similar to those found in cell vesicles after nanoparticle internalization. This result highlights the essential role played by the nanoparticle arrangement in heating performance, uncontrolled in applications. A strategy based on the elaboration of nano-objects able to confine nanocubes in a fixed arrangement is thus considered here to improve the level of control. The obtained specific absorption rate results show that nanoworms and nanospheres with fixed one- and two-dimensional nanocube arrangements, respectively, succeed in reducing the loss of heating power upon agglomeration, suggesting a change in the kind of nano-object to be used in magnetic hyperthermia.

It is shown that akaganéite β-FeOOH provides a good model material to experimentally investigate thermoinduced magnetic moments in antiferromagnetic nanoparticles. We characterize the magnetic properties, exchange field, anisotropy field, and antiferromagnetic susceptibility of bulk akaganéite. In the nanoparticles, we find a drastic enhancement of the antiferromagnetic susceptibility, a phenomenon first predicted by Néel. Also, we find that akaganéite nanoparticles possess a thermoinduced magnetic moment.

2D vanadyl porphyrin layers are shown to possess superior spin coherence and to purvey an optimal interface with superconducting circuits.

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