Paul Crowell

Paul Crowell

Paul Crowell

Head of School of Physics and Astronomy, Professor, School of Physics and Astronomy

Contact

John T. Tate Hall
Room 130-11
116 Church Street Se
Minneapolis, MN 55455
Education

Ph.D., Cornell University, 1994

B.A., Swarthmore College, 1986

Professional Background
  • Faculty member of the University of Minnesota since 1997 and is currently a Professor of Physics
  • General Chair, Joint MMM/Intermag Conference
  • Chair of the APS Topical Group on Magnetism and its Applications, 2012-2013
  • Program Committee Seventh International School of Spintronics and Quantum Information Technology, Japan, 2011
  • Organizer, Focus Session on Spin-Dependent Phenomena in Semiconductors, APS March Meeting, 2010
  • Program Committee, Conference on Magnetism and Magnetic Materials, 2005-2008, 2010
  • Program Co-Chair, Conference on Magnetism and Magnetic Materials, Austin, 2008
Scientific & Professional Societies
Fellow, American Physical Society
Research Interests

My research focuses on spin dynamics and transport in ferromagnets and ferromagnet-semiconductor heterostructures. The first project examines the role of non-equilibrium effects in spin transport in hybrid ferromagnet/semiconductor structures. The materials development for this work is carried out in collaboration with Chris Palmstrom's group at UCSB, who is a collaborator in CSPIN. In recent years, we have succeeded in fabricating simple devices that can be used to test theories of spin transport across interfaces as well as of spin dynamics in the presence of spin-orbit and hyperfine interactions. Similar questions, particularly about the role of interfaces, appear in studies of spin transport in all-metallic heterostructures, a research project that is being carried out in collaboration with Professor Chris Leighton and supported by Seagate. In C-SPIN I am also working on spin-transport in graphene (in collaboration with Steve Koester) and (with Palmstrom) on integrating highly polarized materials into heterostructures with strong spin-orbit coupling.

Honors and Awards
  • Fellow, American Physical Society, 2008
  • McKnight Presidential Fellow, University of Minnesota, 2004-2007
  • Sloan Foundation Fellow, 1999-2001
  • McKnight Land Grant Professor, University of Minnesota 1999-2001
Selected Publications
  1. T.A. Peterson, A.P. McFadden, C.J. Palmstrøm, and P.A. Crowell, Influence of the magnetic proximity effect on spin-orbit torque efficiencies in ferromagnet/platinum bilayersPhys. Rev. B 97, 020403(R) (2018)
  2. Y. Anugrah, J. Hu, G. Stecklein, P.A. Crowell, and S.J. Koester, Independent gate control of injected and detected spin currents in CVD graphene nonlocal spin valvesAIP Advances 8, 015129 (2018)
  3. J.D. Watts, J.S. Jeong, L. O’Brien, K.A. Mkhoyan, P.A. Crowell, and C. Leighton, Room Temperature Spin Kondo Effect and Intermixing in Co/Cu Non-Local Spin ValvesAppl. Phys. Lett. 110, 222407 (2017)
  4. K.-W. Kim, L. O'Brien, P.A. Crowell, C. Leighton, and M.D. Stiles, Theory of Kondo suppression of spin polarization in nonlocal spin valvesPhys. Rev. B 95 104404 (2017)
  5. G. Stecklein, P.A. Crowell, Jing Li, Y. Anugrah, Q. Su, and S. Koester, Contact-induced relaxation in graphene non-local spin valvesPhys. Rev. Applied 6, 054015 (2016)
  6. T.A. Peterson, S.J. Patel, C.C. Geppert, K.D. Christie, A. Rath, D. Pennachio, M.E. Flatté, P.M. Voyles, C.J. Palmstrøm, and P.A. Crowell, Spin injection and detection up to room temperature in Heusler alloy/n-GaAs spin valvesPhys. Rev. B 94, 235309 (2016)
  7. A.K. Smith, M. Jamali, G. Stecklein, P.A. Crowell, and J.P. Wang, Demonstration of nonlocal lateral spin valve devices fabricated with a versatile top-down fabrication processIEEE Magnetics Letters 7, 3103604 (2016)
  8. C. Liu, S.J. Patel, T.A. Peterson, C.C. Geppert, K.D. Christie, C.J. Palmstrøm, and P.A. Crowell, Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonanceNature Communications 7, 10296 (2016)
  9. L. O’Brien, D. Spivak, J.S. Jeong, K.A. Mkhoyan, P.A. Crowell, and C. Leighton, Interdiffusion-controlled Kondo suppression of injection efficiency in metallic non-local spin valvesPhys. Rev. B 93, 014413 (2016)
  10. K.D. Christie, C.C. Geppert, S.J. Patel, Q.O. Hu, C.J. Palmstrøm, and P.A. Crowell, Knight shift and nuclear spin relaxation in Fe/n-GaAs heterostructures,” Phys. Rev. B 92, 155204 (2015)Phys. Rev. B 92, 155204 (2015)
  11. N.J. Harmon, T.A. Peterson, C.C. Geppert, S.J. Patel, C.J. Palmstrøm, P.A. Crowell, and M.E. Flatté, Anisotropic spin relaxation in n-GaAs from strong inhomogeneous hyperfine fields produced by the dynamical polarization of nucleiPhysical Review B 92 140201(R) (2015)
  12. Y. Anugrah, M.C. Robbins, P.A. Crowell, and S.J. Koester, Determination of the Schottky barrier height of ferromagnetic contacts to few-layer phosphoreneApplied Physics Letters 106 103108 (2015)
  13. C. Liu, Y. Boyko, C.C. Geppert, K.D. Christie, G. Stecklein, S.J. Patel, C.J. Palmstrøm, and P.A. Crowell, Electrical detection of ferromagnetic resonance in ferromagnet/n-GaAs heterostructures by tunneling anisotropic magnetoresistanceApplied Physics Letters 105 212401 (2014)
  14. A.T. Galkiewicz, L. O’Brien, P.S. Keatley, R.P. Cowburn, and P.A. Crowell, Resonance in magnetostatically coupled transverse domain wallsPhysical Review B 90 024420 (2014)
  15. L. O’Brien, M.J. Erickson, D. Spivak, H. Ambaye, R.J. Goyette, V. Lauter, P.A. Crowell, and C. Leighton, Kondo physics in non-local metallic spin transport devicesNature Communications 5, 2937 (2014)  [download O-Brien_NatureCommunications_5_3927_2014.pdf]
  16. T.Y. Chen, A.T. Galkiewicz, and P.A. Crowell, Phase Diagram of Magnetic Vortex DynamicsPhysical Review B 180406(R) (2012)
  17. Y. Zhang, H. Zhao, A. Lyle, P.A. Crowell, and J.P. Wang, High power and low critical current spin torque oscillation from a magnetic tunnel junction with a built-in hard axis polarizerApplied Physics Letters 100, 032405 (2012)
  18. T.Y. Chen, M.J. Erickson, P.A. Crowell, and C. Leighton, Surface Roughness Dominated Pinning Mechanism of Magnetic Vortices in Soft Ferromagnetic FilmsPhys. Rev. Lett. 109, 097202 (2012) [download Chen_Submitted.pdf]
  19. Q.O. Hu, E.S. Garlid, P.A. Crowell, and C.J. Palmstrøm, Spin accumulation near Fe/GaAs(001) interfaces: The role of semiconductor band structurePhysical Review B, 84 085306 (2011)
  20. P.A. Crowell and S.A. Crooker, Spin Transport in Ferromagnet/III-V Semiconductor HeterostructuresHandbook of Spin Transport and Magnetism, edited by E.Y. Tsymbal and I. Zutic (2011) [download Crowell_Chapter23.pdf]
  21. Y.S. Zhang, H. Zhao, A. Lyle, P.A. Crowell, and J.P. Wang, Spin torque oscillation modes of a dual magnetic tunneling junctionJournal of Applied Physics 109, 07D307 (2011)
  22. E.S. Garlid, Q.O. Hu, M.K. Chan, C.J. Palmstrøm, and P.A. Crowell , Electrical Measurement of the Direct Spin Hall Effect in Fe/InxGa1-xAs HeterostructuresPhysical Review Letters 105, 156602 (2010)
  23. T.Y. Chen and P.A. Crowell, Non-linear dynamics of a magnetic vortexIEEE Transactions on Magnetics 46, 1457 (2010)
  24. R.L. Compton, T.Y. Chen, and P.A. Crowell, Magnetic vortex dynamics in the presence of pinningPhysical Review B 81 144412 (2010)
  25. B.D. Schultz, N. Marom, D. Naveh, X. Lou, C. Adelmann, J. Strand, P.A. Crowell, L. Kronik, and C.J. Palmstrøm , Spin injection across the Fe/GaAs interface: Role of interfacial orderingPhys. Rev. B 80, 201309 (2009) [abstract]
  26. M.K. Chan, Q.O. Hu, J. Zhang, T. Kondo, C.J. Palmstrøm, and P.A. Crowell , Hyperfine interactions and spin transport in ferromagnet-semiconductor heterostructuresPhys. Rev. B 80, 161206(R)(2009) [abstract]
  27. S.A. Crooker, E.S. Garlid, A.N. Chantis, D.L. Smith, S.M. Reddy, Q.O. Hu, T. Kondo, C.J. Palmstrøm, and P.A. Crowell, Bias-controlled sensitivity of ferromagnet/semiconductor electrical spin detectorsPhysical Review B 80 041305(R) (2009) [abstract]
  28. X. Lou, C. Adelmann, S.A. Crooker, E.S. Garlid, J. Zhang, S.M. Reddy, S.D. Flexner, C.J. Palmstrøm, and P.A. Crowell, Electrical Detection of Spin Transport in Lateral Ferromagnet-Semiconductor DevicesNature Physics 3, 197 (2007)
  29. R.L. Compton and P.A. Crowell, Dynamics of a Pinned Magnetic VortexPhys. Rev. Lett. 97, 137202 (2006)
  30. C. Adelmann, J.L. Hilton, B.D. Schultz, S. McKernan, C.J. Palmstrøm, X. Lou, H.-S. Chiang, and P.A. Crowell, Spin Injection from Perpendicular Magnetized Ferromagnetic δ-MnGa into (Al,Ga)As HeterostructuresAppl. Phys. Lett. 89, 112511 (2006)
  31. X. Lou, C. Adelmann, M. Furis, S.A. Crooker, C.J. Palmstrøm, and P.A. Crowell, Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor InterfacePhys. Rev. Lett. 96, 176603 (2006).
  32. J.P. Park and P.A. Crowell, Interactions of Spin Waves with a Magnetic VortexPhys. Rev. Lett. 95, 167201 (2005)
  33. S.A. Crooker, M. Furis, X. Lou, C. Adelmann, D.L. Smith, C.J. Palmstrøm, and P.A. Crowell, Imaging spin injection and accumulation in lateral ferromagnet/semiconductor devicesScience 309, 2191(2005)
  34. C. Adelmann, X. Lou, J. Strand, C.J. Palmstrøm, and P.A. Crowell, Spin Injection and Relaxation in Ferromagnet-Semiconductor HeterostructuresPhys. Rev. B 71 121301(R) (2005).
  35. C. Bayer, J.P. Park, H. Wang, M. Yan, C.E. Campbell, and P.A. Crowell, Spin Waves in an Inhomogeneously Magnetized StripePhys. Rev. B 69, 134401 (2004)
  36. Iori Tanabe et al., Chemical vapor deposition WS2 Brillouin zone-ddge and -center band structure characteristicsAppl. Phys. Lett. 108 252103 (2016)
  37. K.D. Christie, C.C. Geppert, S.J. Patel, Q.O. Hu, C.J. Palmstrøm, and P.A. Crowell, Knight shift and nuclear spin relaxation in Fe/n-GaAs heterostructures,” Phys. Rev. B 92, 155204 (2015)Phys. Rev. B 92, 155204 (2015)
  38. M.R. Fitzsimmons, B.J. Kirby, N.W. Hengartner, F. Trouw, M.J. Erickson, S.D. Flexner, T. Kondo, C. Adelmann, C.J. Palmstrøm, P.A. Crowell, W.C. Chen, T.R. Gentile, J.A. Borchers, C.F. Majkrzak, and R. Pynn , Suppression of Nuclear Polarization near the Surface of Optically Pumped GaAsPhys. Rev. B. (2007)
  39. M.K. Chan, J.S. Parker, P.A. Crowell, and C. Leighton, Identification and Separation of Two Distinct Contributions to the Training Effect in Polycrystalline Exchange Biased Co/FeMn BilayersPhys. Rev. B 77 014420(2008)
  40. J. Strand, X. Lou, C. Adelmann, B.D. Schultz, A.F. Isakovic, C.J. Palmstrøm, and P.A. Crowell, Electron Spin Dynamics and Hyperfine Interactions in Fe/Al0.1Ga0.9As/GaAs Spin Injection HeterostructuresPhys. Rev. B 72, 155308 (2005).
  41. J. Strand, A.F. Isakovic, X. Lou, P.A. Crowell, B.D. Schultz, and C.J. Palmstrøm, Nuclear Magnetic Resonance in a Ferromagnet-Semiconductor HeterostructureAppl. Phys. Lett. 83, 3335 (2003)
  42. J. Strand, B.D. Schultz, A.F. Isakovic, C.J. Palmstrøm, and P.A. Crowell, Dynamical Nuclear Polarization by Electrical Spin Injection in Ferromagnet-Semiconductor HeterostructuresPhys. Rev. Lett. 91, 036602 (2003)
  43. J.P. Park, P. Eames, D.M. Engebretson, J. Berezovsky, and P.A. Crowell, Spatially Resolved Dynamics of Localized Spin-Wave Modes in Ferromagnetic WiresPhys. Rev. Lett. 89, 277201 (2002)
  44. J.P. Park, P. Eames, D.M. Engebretson, J. Berezovsky, and P.A. Crowell, Imaging of Spin Dynamics in Closure Domain and Vortex StructuresPhys. Rev. B 67, 020403R (2003)
  45. J. N. Heyman, H. Wrage, C. Lind, D .Hebert, P. Neocleous, P. A. Crowell, T. Muller, and K. Unterrainer, Terahertz Emission from Magneto-plasma Oscillations in SemiconductorsProceedings of SPIE, accepted for publication (2002).
  46. M. Yan, J. Berezovsky, P. A. Crowell, and C. E. Campbell, Simulations of Magnetic Dynamics in Iron-Cobalt FilmsCondensed Matter Theories Vol 17, edited by M. P. Das and F. Green (Nova, New York, 2003, p. 295.
  47. D. M. Engebretson, J. Berezovsky, J. P. Park, L. C. Chen, C. J. Palmstrom, and P. A. Crowell, Time-Domain Ferromagnetic Resonance in Epitaxial Thin FilmsJ. Appl. Phys. 91, 8040 (2002)
  48. A. F. Isakovic, D. M. Carr, J. Strand, B. D Schultz, C. J. Palmstrom, and P. A. Crowell, Optically Pumped Transport in Ferromagnet-Semiconductor Schottky DiodesJ. Appl. Phys. 91, 7261 (2002)
  49. A. F. Isakovic, D. M. Carr, J. Strand, B. D. Schultz, C. J. Palmstrom, and P.A. Crowell, Optical Pumping in Ferromagnet-Semiconductor Heterostructures: Magneto-optics and Spin TransportPhys. Rev. B 64, 161304R (2001)
  50. J. N. Heyman, P. Neocleous, D. Hebert, P. A. Crowell, T. Muller, and K. Unterrainer, Terahertz Emission from GaAs and InAs in a Magnetic FieldPhys. Rev. B 64, 085202 (2001)
  51. A. F. Isakovic, J. Berezovsky, P. A. Crowell, L. C. Chen, D. M. Carr, B. D. Schultz, and C. J. Palmstrom, Control of Magnetic Anisotropy in Fe1-xCox Films on Vicinal GaAs and Sc1-yEryAs SurfacesJournal of Applied Physics 89, 6674 (2001)
  52. M. Veum, C. Pettersen, P. Mach, P. A. Crowell, and C. C. Huang, Temperature Variation of Film Tension Measured by a Vibrating Membrame Tensiometer, Phys. Rev. E. 61, R2192 (2000)
  53. L. C. Chen, J. W. Dong, B. D. Schultz, C. J. Palmstrom, J. Berezovsky, A. Isakovic, P. A. Crowell, and N. Tabat, Epitaxial Ferromagnetic Metal/GaAs (001) HeterostructuresJ. Vac. Sci. Tech. B 18, 2057 (2000)
  54. B. Beschoten, P. A. Crowell, I. Malajovich, D. D. Awschalom, F. Matsukura, A. Shen, and H. Ohno, Magnetic Circular Dichroism Studies of Carrier-Induced Ferromagnetism in (Ga1-xMnx)AsPhys. Rev. Lett. 83, 3073 (1999)
  55. P. A. Crowell, V. Nikitin, J. A. Gupta, D. D. Awschalom, F. Flack and N. Samarth, Optical Spectroscopy of II-VI (Magnetic) Semiconductor Quantum Dots, Physica E 2, 854 (1998)
  56. P. A. Crowell, D. K. Young, S. Keller, E. L. Hu, and D. D. Awschalom, Near-field scanning optical spectroscopy of an InGaN quantum well, Appl. Phys. Lett. 72, 927 (1998)
  57. V. Nikitin, P. A. Crowell, J. A. Gupta, D. D. Awschalom, F. Flack, and N. Samarth, Zero-dimensional excitonic confinement in locally strained Zn[sub 1 - x]Cd[sub x]Se quantum wells, Appl. Phys. Lett. 71, 1213 (1997).

Advisees & Collaborators

Undergraduate Students:

  • Joe Dill

Graduate Students:

  • James Etheridge
  • Zhen Jiang
  • Bill Peria
  • Han Yu

Postdoctoral Researchers:

  • Tao Qu