Transition Metal Pnictide Nanoparticles: Synthesis and Assembly of Novel Magnetic Materials

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Fundamental issues pertaining to the exploitation of magnetic nanomaterials in devices will be explored for a series of transition metal pnictide phases with promising attributes for spintronic or magnetic data storage applications. The fundamental factors that underpin the nucleation and growth of manganese arsenide (MnAs) and manganese phosphide (MnP) will be elucidated using arrested precipitation strategies with conventional and microwave heating. Once prepared, the role of particle size on the first-order phase transition in MnAs, and the effect of different kinds of anisotropy on the coercive properties of MnP, will be studied. The factors that control product stoichiometry in iron phosphides (FexP where x=1, 2, or 3) will be discerned by a detailed study of reactant stoichiometry, reactant activity, temperature and time. Single-phase nanoparticulate (FexP) samples will then be used to determine the effects of short physical length scales on complex magnetic ordering and coercivity. This work will also explore the condensation of discrete MnP nanoparticles into gel-structures and the influence of the aggregate and pore structure on dipole-dipole interactions between discrete particles. In the course of pursuing this research, graduate and undergraduate student researchers will develop critical thinking skills and proficiency in scientific writing and communication, as well as learn cutting-edge research techniques, including electron microscopy.%%%Due to their small footprint and size-tunable properties, nanomaterials promise to revolutionize a wide range of technologies from computer processing and data storage to biological imaging of disease states. However, the exploitation of nanomaterials in actual devices is limited by progress in a number of fundamental areas. These include: methods for preparing single-phase, low-polydispersity samples of particles with control of shape and size; methods for assembling particles into functional architectures; quantification of the relationship between the observed physical properties and the size, shape, and composition of the material; and evaluation of the influence of particle-particle interactions in 3 D architectures. This project will address these fundamental issues in the context of a series of transition metal pnictide phases with promising attributes for spintronic or magnetic data storage applications, but which have not been systematically evaluated on the nanoscale: MnAs, MnP, and Fe-P (FeP, Fe2P, Fe3P). In the course of pursuing this research, graduate and undergraduate students will develop critical thinking skills and proficiency in scientific writing and communication, as well as learning cutting-edge research techniques and how to work in an interdisciplinary team. So prepared, these students will be among the vanguard of new researchers employed in developing the next generation of advanced technologies.