Magnetic materials are ubiquitous in society, providing functionality to advanced devices, sensors and motors of every kind. As the magnetic force maintains strength over large distances, it allows for communication between components that are physically separated. This unique property permits the conversion of electrical to mechanical energy, assists microwave devices in telecommunications, transmits and distributes electric power and provides the basis for data storage systems. Magnetic materials are increasingly employed in medical applications, not only in NMR diagnostic equipment but also in specialized targeted cancer treatments and drug delivery protocols. It is anticipated that specialized engineering of magnetic materials and careful tailoring of their properties will enable a new generation of stronger and more responsive materials and devices that can significantly impact the way we use and store energy. Current research is devoted to understanding magnetostructural transitions, which comprise simultaneous magnetic and structural phase changes. These transitions are attracting new attention due to the recognition that they underlie an assortment of “extreme” phenomena with important technological implications, such as Colossal Magnetoresistance (CMR) of interest for magnetic sensors in the recording industry; the giant Magnetocaloric Effect (MCE) under intense development for CFC-free magnetic refrigeration, and exceptional magnetomechanical behavior for actuators. Magnetostructural transitions may be driven by multitude of physical inputs (magnetic field, temperature, pressure, electric field), implying they may be manipulated to yield a tailored functional response. Our research employs advanced materials probes and techniques (magnetic measurement, advanced electron microscopy and specialized synchrotron scattering and spectroscopic techniques) that are available both at Northeastern University and at the Brookhaven National Laboratory in Long Island, New York.
Articles
Magnetic signature of symmetry reduction in epitaxial La₀.₆₇Sr₀.₃₃MnO₃ films (with Radhika Barua and D. Heiman), Physics Faculty Publications (2011)
The magnetic properties of epitaxially grown La0.67Sr0.33MnO3 perovskite thin films were investigated to elucidate an...
Universal properties of linear magnetoresistance in strongly disordered MnAs-GaAs composite semiconductors (with H. G. Johnson, S. P. Bennett, R. Barua, and D. Heiman), Physics Faculty Publications (2010)
Linear magnetoresistance (LMR) occurs in semiconductors as a consequence of strong electrical disorder and is...
Determining magnetic nanoparticle size distributions from thermomagnetic measurements (with R. S. DiPietro, H. G. Johnson, S. P. Bennett, T. J. Nummy, and D. Heiman), Physics Faculty Publications (2010)
Thermomagnetic measurements are used to obtain the size distribution and anisotropy of magnetic nanoparticles. An...
Preprints
Determining magnetic nanoparticle size distributions from thermomagnetic measurements (with R. S. DiPietro, H. G. Johnson, S. P. Bennett, T. J. Nummy, and D. Heiman), Physics Faculty Publications (2010)
Thermomagnetic measurements are used to obtain the size distribution and anisotropy of magnetic nanoparticles. An...