Web Release Date: January 9,
One-Pot Synthesis and Characterization of Size-Controlled Bimagnetic FePt-Iron Oxide Heterodimer Nanocrystals
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Scuola Superiore ISUFI, University of Salento, Distretto Tecnologico ISUFI, via per Arnesano km 5, I-73100 Lecce, Italy, National Nanotechnology Laboratory of CNR-INFM, Unità di Ricerca IIT, via per Arnesano km 5, I-73100 Lecce, Italy, Laboratoire de Physique et de Chimie des Nanoobjets-INSA, 135 Avenue de Rangueil, F-31077 Toulouse, France, CNR-Istituto di Cristallografia (IC), via Amendola 122/O, I-70126, Bari, Italy, Dipartimento di Fisica "A. Volta", Università di Pavia, and Unità CNR-INFM and CNISM, via Bassi 6, I-27100, Pavia, Italy, and Istituto di Fisiologia Generale e Chimica Biologica "G. Esposito", Milano and S3-CNR-INFM, Modena, Italy
Received October 19, 2007
Abstract:
A one-pot, two-step colloidal strategy to prepare bimagnetic hybrid nanocrystals (HNCs), comprising size-tuned fcc FePt and inverse spinel cubic iron oxide domains epitaxially arranged in a heterodimer configuration, is described. The HNCs have been synthesized in a unique surfactant environment by temperature-driven sequential reactions, involving the homogeneous nucleation of FePt seeds and the subsequent heterogeneous growth of iron oxide. This self-regulated mechanism offers high versatility in the control of the geometric features of the resulting heterostructures, circumventing the use of more elaborate seeded growth techniques. It has been found that, as a consequence of the exchange coupling between the two materials, the HNCs exhibit tunable single-phase-like magnetic behavior, distinct from that of their individual components. In addition, the potential of the heterodimers as effective contrast agents for magnetic resonance imaging techniques has been examined.
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