Hans M Christen

Hans Christen

Hans M Christen

Director, Neutron Scattering Division

Bio

Hans Christen received a Ph.D. in Physics from the Ecole Polytechnique Fédérale, Lausanne, Switzerland, in 1994 for research performed at the IBM Zurich Research Laboratory. After a post-doctoral appointment at ORNL, he joined Neocera, Inc., where he worked on development of pulsed-laser deposition equipment and scanning microwave measurements. He joined ORNL as a staff member in 2000 and led the Thin Films and Nanostructures Group from 2006 to 2013. In 2013, he became Associate Division Director within the Materials Science and Technology Division. He served as ORNL Manager for the DOE Materials Sciences and Engineering Program from 2011 to 2013. From January 2014 through August 2018, he led the Center for Nanophase Materials Sciences, before taking the role of Director, Neutron Scattering Division, in September 2018. Hans’s research has focused on the effects of epitaxial strain, spatial confinement, and interfacial mechanisms on the properties of complex-oxide thin films, in particular ferromagnetic, ferroelectric, and multiferroic perovskites.

Awards

Fellow, American Physical Society

Publications

More than 180 peer reviewed scientific publications (see https://scholar.google.com/citations?user=BIqePJAAAAAJ, and http://orcid.org/0000-0001-8187-7469), including:

"Electrically reversible cracks in an intermetallic film controlled by an electric field." Z.Q. Liu, H. H. Liu, M.D. Biegalski, ... H. M. Christen, and R. Ramesh, Nature Commun. 9, 41 (2018)

"Origin of thickness dependence of structural phase transition temperatures in highly strained BiFeO3 thin films." Y. Yang, C. Beekman, *W. Siemons, C.M. Schlepütz, N. Senabulya, R. Clarke, and H.M. Christen, APL Mater. 4, 036106 (2016)

"Full Electroresistance Modulation in a Mixed-Phase Metallic Alloy." Z.Q. Liu, L. Li, J.D. Clarkson, S.L. Hsu, A.T. Wong, S.S. Fan, M.-W. Lin, C.M. Rouleau, T.Z. Ward, H.N. Lee, A.S. Sefat, H.M. Christen, and R. Ramesh, Phys. Rev. Lett. 116, 097203 (2016)

“Understanding Strain-Induced Phase Transformations in BiFeO3 Thin Films,” H. Dixit, C. Beekman, C.M. Schlepütz, W. Siemons, Y. Yang, N. Senabulya, R. Clarke, M. Chi, H.M. Christen, and V.R. Cooper, Advanced Science 2015, 1500041 (2015)

“Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxides targets,” A. Herklotz, K. Dörr, T.Z. Ward, G. Eres, H.M. Christen, and M.D. Biegalski, Appl. Phys. Lett. 106, 131601 (2015)

“Super switching and control of in-plane ferroelectric nanodomains in strained thin films,” S. Matzen, O. Nesterov, G. Rispens, J.A. Heuver, M. Biegalski, H.M. Christen, and B. Noheda,
Nature Comm. 5, 4415 (2014)

“A complete strain-temperature phase diagram for BiFeO3 films on SrTiO3 and LaAlO3 (0 0 1) substrates,” W. Siemons, C. Beekman, G.J. MacDougall, J.L. Zarestky, S.E. Nagler, and H.M. Christen, J. Phys. D: Appl. Phys. 47, 034011 (2014)

“Tuning the Spin State in LaCoO3 Thin Films for Enhanced High-Temperature Oxygen Catalysis,” W.T. Hong, M. Gadre, Y.L. Lee, M.D. Biegalski, H.M. Christen. D. Morgan, and Y. Shao-Horn, J. Phys. Chem. Lett. 4, 2493 (2013)

“Phase Transitions, Phase Coexistence, and Piezoelectric Switching Behavior in Highly Strained BiFeO3 Films,” C. Beekman, W. Siemons, T.Z. Ward, M. Chi, J. Howe, M.D. Biegalski, N. Balke, P. Maksymovych, A.K. Farrar, J.B. Romero, P. Gao, X.Q. Pan, D.A. Tenne, and H.M. Christen, Adv. Mat. 25, 5561 (2013)

“Strain-controlled switching kinetics of epitaxial PbZr0.52Ti0.48O3 films, A. Herklotz, E.-J. Guo, M.D. Biegalski, H.-M. Christen, L. Schultz, and K. Dörr, New J. Phys. 15, 073021 (2013)

“Room-Temperature Multiferroic Hexagonal LuFeO3 films,” W. Wang, J. Zhao, W. Wang. Z. Gai. N. Balke, M. Chi, H.N. Lee, W. Tian, L. Zhu, X. Cheng, D.J. Keavney, J. Yi, T.Z. Ward, P.C. Snijders, H.M. Christen, W. Wu, J. Shen, and X. Xu, Phys. Rev. Lett. 110, 237601 (2013)

"Strong polarization enhancement in asymmetric three-component ferroelectric superlattices," H.N. Lee, H.M. Christen, M.F. Chisholm, C.M. Rouleau, and D.H. Lowndes, Nature 433, 395 (2005)

"Dielectric properties of sputtered SrTiO3 films." H.M. Christen, J. Mannhart, E.J. Williams, and Ch. Gerber, Phys. Rev. B 49, 12095 (1994)

Patents

Ferroelectric Tunneling Element and Memory Applications which Utilize the Tunneling Element; US 7,759,713 B2 (Jun. 20, 2010); S.V. Kalinin, H.M. Christen, A.P. Baddorf, V. Meunier, and H.N. Lee

Apertured Probes for Localized Measurements of a Material’s Complex Permittivity and Fabrication Method; US 6,959,481 B2 (Nov. 1, 2005); R.L. Moreland, H.M. Christen, V.V. Talanov, and A.R. Schwartz

System and Method for Quantitative Measurements of a Material’s Complex Permittivity with Use of Near-Field Microwave Probes; US 6,856,140 B2 (Feb. 15, 2005); V.V. Talanov, R.L. Moreland, A.R. Schwartz, and H. M. Christen

Apertured Probes for Localized Measurements of a Material’s Complex Permittivity and Fabrication Method; US 6,680,617 B2 (Jan. 20, 2004); R.L. Moreland, H.M. Christen, V.V. Talanov, and A.R. Schwartz

Apparatus for Localized Measurements of Complex Permittivity of a Material; US 6,597,185 B1 (Jul. 22, 2003); V.V. Talanov, H.M. Christen, and R. Moreland

Combinatorial Synthesis System; US 6,491,759 B1 (Dec. 10, 2002); H.M. Christen and S.D. Silliman

Scanned Focus Deposition System; US 6,497,193 B2 (Dec. 24, 2002); H.M. Christen

Facilities Used

Center for Nanophase Materials Sciences
High Flux Isotope Reactor
Spallation Neutron Source
Advanced Photon Source
SLAC National Accelerator Laboratory

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