Dr. Coffey’s research interests include both magnetism and the materials science of nano-scale interfaces.

Materials systems such as the high magneto-crystalline anisotropy FePt ordered intermetallic phases are of special interest because of a strong relationship between magnetic properties and nanoscale microstructure. Additionally, this system promises to be an ideal model system for the study of bulk permanent magnet materials because of the large range of microstructure variation that can be readily obtained. Dr. Coffey’s work includes a study of magnetic switching in various nanoscale permanent magnet thin films used for magnetic recording as well as the processing, structure, and properties of FePt and other L10 phase magnetic thin films, as well as giant magnetoresistance is soft magnetic thin film structures.

The oxidative and thermal stability of nanoscale microstructures is important to the potential use of such devices and effected greatly by relatively large amount of interfacial area present in such devices. Dr. Coffey’s work and interests include the oxidation and interdiffusion of thin film structures where the kinetics are strongly dependent on interfacial transport.

Selected Publications

K.R. Coffey, T. Thomson, and J.-U. Thiele, “The angular dependence of the switching field of thin film longitudinal and perpendicular magnetic recording media,” submitted for publication 2002, Journal of Applied Physics.

J.-U. Thiele, K.R. Coffey, M.F. Toney, J.A. Hedstrom, and A.J. Kellock , “Temperature dependent magnetic properties of highly chemically ordered Fe55-xNixPt45 L10 films,” Journal of Applied Physics, June 1, 2002.

R.A. Ristau, K. Barmak, K.R. Coffey, and J.K. Howard, “Grain growth in ultrathin films of CoPt and FePt,” Journal of Materials Research, vol. 14, no. 8, p. 3263-3270, Aug. 1999.

K.R. Coffey, T.L. Hylton, M.A. Parker, and J.K. Howard, “Thin-film structures for low-field granular giant magnetoresistance, ” Scripta Metallurgica et Materialia, vol. 33, no. 10-11, p. 1593-1602. Dec. 1995.

K.R. Coffey, M.A. Parker, J. K. Howard, “High anisotropy L1(0) thin films for longitudinal recording,” IEEE Transactions on Magnetics, vol. 31, no. 6, pt. 1, p. 2737-39, Nov. 1995.

K.R. Coffey and K. Barmak, "A new model for grain boundary diffusion and nucleation in thin film reactions," Acta Metallurgica et Materialia, vol. 42, no. 8, p. 2905-2911, Aug. 1994.

T.L. Hylton, K.R. Coffey, M.A. Parker, and J.K. Howard, "Giant magnetoresistance at low fields in discontinuous NiFe-Ag multilayer thin films," Science, vol. 261, no. 5124, p. 1021-4, Aug. 1993.

K.R. Coffey, T.L. Hylton, M.A. Parker, and J.K. Howard, "Granular giant magnetoresistance at low fields in bilayer thin films," Applied Physics Letters, vol. 63, no. 11, p. 1579-81, Sept. 1993.

K.R. Coffey, K. Barmak, D.A. Rudman, and S. Foner, "Thin film reaction kinetics of niobium/aluminum multilayers," Journal of Applied Physics, vol. 72, no. 4, p. 1341-9, Aug. 1992.

K.R. Coffey, L.A. Clevenger, K. Barmak, D.A. Rudman, and C.V. Thompson, "Experimental evidence for nucleation during thin film reactions," Applied Physics Letters, vol. 55, no. 9, p. 852-4, Aug 1989.