Professor of Physics
Department of Physics
fhellman@physics.berkeley.edu
(510) 642-6135

Research Expertise and Interest

condensed matter physics and materials science

Description

My research group is concerned with the properties of novel magnetic, semiconducting, and superconducting materials especially in thin film form. We use specific heat, magnetic susceptibility, electrical resistivity, and other measurements as a function of temperature in order to test and develop models for materials which challenge our understanding of metallic behavior.



Current research includes: effects of spin on transport and tunneling, including studies of amorphous magnetic semiconductors and spin injection from ferromagnets into Si; finite size effects on magnetic and thermodynamic properties; formation of perpendicular magnetic anisotropy in magnetic thin films and effects of the vapor-deposition growth process on the structure of thin film amorphous and crystalline materials.



We also have an extensive effort in development of calorimetry for thin films, small bulk samples, and nano-scale biological systems. We use Si-microfabrication techniques to create membrane-based micro/nanocalorimeters that allow us to measure films weighing micrograms or less from 1-500K and in magnetic fields at present to 8T. We are working with researchers at the national high magnetic field lab to extend the magnetic field range to 45T in steady state and 100T in pulsed fields, and the temperature range to 0.3K.

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