Now showing items 1-20 of 58

    • Synthesis of Mn-Zn ferrite from Na2O-B2O3 flux under CO-CO2 ambients 

      Plaskett, T.S.; Shivashankar, S.A.; Gilbert, B.L.; Olson, B.L.; Chien, C.-L.; Herman, D.A. Jr. (American Institute of Physics, 1982-03)
      Synthesis was carried out by dissolving MnO, ZnO, and Fe2O3 in the molar ratio 0.42:0.44:1.07 in fluxes of Na2O:xB2O3 at 900 °C and slow cooling under ambients of CO-CO2 mixtures; x varied from 1.34 to 2.0 and Co-Co2 from ...
    • Magnetic dynamics of La2CuO4 studied by Mossbauer spectroscopy 

      Tang, H.; Gang, X.; Singh, A.; Tesanovic, Z.; Chien, C.-L.; Walker, J.C. (American Institute of Physics, 1990-05-01)
      By doping a very small amount of 57Fe into La2CuO4, Mossbauer spectroscopy has been applied to study the magnetic property of the parent compound. From the measurement of the magnetic hyperfine field at the Fe nuclei for ...
    • A strongly fluctuating quasi-two-dimensional insulator 

      Cooper, A.S.; Espinosa, G.P.; Broholm, C.; Aeppli, G. (American Institute of Physics, 1991-04-15)
      The authors describe neutron-scattering data for SrCr8-xGa4+xO19, a layered compound containing planes of S=3/2 Cr3+ ions which form Kagome lattices. Despite strong antiferromagnetic interactions (θCW≈-500 K), fluctuations ...
    • Effect of spacer material on the magnetic surface anisotropy in ultrathin Fe70B30 multilayer films 

      Hicken, R.J.; Rado, G.T.; Chien, C.-L. (American Institute of Physics, 1991-04-15)
      It has been found recently that the magnetic surface anisotropy Ks in Fe70B30/Ag multilayer films decreases monotonically with magnetic layer thickness (2L) for 2L<16.5 Å. In order to determine possible effects of the ...
    • Comparison of the electron-spin-resonance linewidth in multilayered CuMn spin glasses with insulating versus conducting interlayers 

      Leslie-Pelecky, D.L.; VanWijland, F.; Hoff, C.N.; Cowen, J.A.; Gavrina, A.; Chien, C.-L. (American Institute of Physics, 1994-05-15)
      The temperature-dependent electron-spin-resonance linewidth ΔH(T) may be used to investigate the effect of the geometry and interlayer material on the magnetic properties of multilayered systems. We compare ΔH(T) in ...
    • Strong magnetic fluctuations in transition metal oxides 

      Aeppli, G.; Lee, S.-H.; Broholm, C.; DiTusa, J.F.; Bao, W. (American Institute of Physics, 1996-04-15)
      Most magnets have long-range magnetic order when the thermal energy is less than the local magnetic exchange energy (T<|ΘCW|) effects such as reduced dimensionality and frustration, 1 however, can suppress the ordering ...
    • Studies of deposition order anomaly of exchange coupling in bilayers and trilayers of NiFe and CoO 

      Ambrose, T.; Leifer, K.; Hemker, K.J.; Chien, C.-L.; Ambrose, T.1; Leifer, K.; Hemker, K.J.; Chien, C.L. (American Institute of Physics, 1997-04-15)
      The temperature dependence of the exchange field and coercivity and the effect of deposition order have been studied in a series of bilayer (NiFe/CoO and CoO/NiFe) and trilayer (NiFe/CoO/NiFe) films. A profound difference ...
    • Long-range exchange coupling between a ferromagnet and an antiferromagnet across a nonmagnetic spacer layer 

      Gokemeijer, N.J.; Ambrose, T.; Chien, C.-L.; Wang, N.; Fung, K.K. (American Institute of Physics, 1997-04-15)
      The antiferromagnet/ferromagnet exchange coupling giving rise to a shifted hysteresis loop has usually been considered an interfacial effect. We show evidence that this exchange coupling between an antiferromagnet (CoO) ...
    • Dependence of exchange coupling on antiferromagnetic layer thickness in NiFe/CoO bilayers 

      Ambrose, T.; Chien, C.-L. (American Institute of Physics, 1998-06-01)
      A systematic study of the dependence of exchange coupling in NiFe/CoO bilayers on CoO layer thickness tAF from 5 to 500 Å has been made. For large CoO thicknesses (tAF>100 Å), the exchange field varies as 1/tAF, whereas ...
    • Memory effects of exchange coupling in CoO/Ni81Fe19 bilayers 

      Gokemeijer, N.J.; Chien, C.-L. (American Institute of Physics, 1999-04-15)
      By changing the field-cooling procedure, the value and even the sign of the exchange field HE in CoO/Ni81Fe19 bilayers can be greatly altered. The value of HE can be made to vanish at any temperature below TN. We also show ...
    • Doubly exchange-biased NiCoO/NiFe/Cu/NiFe/NiCoO spin valves 

      Ambrose, T.; Liu, K.; Chien, C.-L. (American Institute of Physics, 1999-04-15)
      A new type of doubly exchange-biased Ni50Co50O/NiFe/Cu/NiFe/Ni30Co70O spin-valve structure, with two ferromagnetic layers exchange biased in opposite directions by two different antiferromagnetic layers is demonstrated. ...
    • Giant positive magnetoresistance of Bi nanowire arrays in high magnetic fields 

      Hong, Kimin; Yang, F.Y.; Liu, Kai; Reich, D.H.; Searson, P.C.; Chien, C.-L.; Balakirev, F.F.; Boebinger, G.S. (American Institute of Physics, 1999-04-15)
      We have studied the magnetoresistance of electrodeposited Bi wires with diameters between 200 nm and 2 μm in magnetic fields up to B=55 T. In zero field, the resistance increases with decreasing temperature, indicating ...
    • Comparison of surface spin wave modes at Fe/MnF2 and Fe/Mn interfaces 

      Siu, I.L.; Islam, M.N.; Walker, J.C. (American Institute of Physics, 2000-11-01)
      We have studied the thermal demagnetization in semi-infinite ferromagnets in Fe/MnF2 and Fe/Mn bilayers using Mössbauer spectroscopy. We find that the hyperfine field at the Fe/MnF2 interface follows a quasilinear temperature ...
    • Longitudinal and perpendicular exchange bias in FeMn/(FeNi/FeMn)n multilayers 

      Sun, L.; Zhou, S.M.; Searson, P.C.; Chien, C.-L. (American Institute of Physics, 2003-05-15)
      Exchange bias in ferromagnetic (FM)/antiferromagnetic (AF) bilayers is usually investigated in the longitudinal configuration with the exchange coupling established in the film plane. In this work, we report on the ...
    • Magnetic properties of epitaxial Mn-doped ZnO thin films 

      Cheng, X.M.; Chien, C.-L. (American Institute of Physics, 2003-05-15)
      Epitaxial ZnO thin films doped with 7% Mn have been made by reactive rf magnetron sputtering onto (112_0) sapphire substrates at 400°C. X-ray diffraction measurements reveal that the Zn0.93Mn0.07O film has a (0001) wurtzite ...
    • Magnetic core loss of ultrahigh strength FeCo alloys 

      Cheng, X.M.; Zhang, X.K.; Zhang, D.Z.; Lee, S.H.; Duckham, A.; Weihs, T.P.; Cammarata, R.C.; Chien, C.-L. (American Institute of Physics, 2003-05-15)
      Hiperco® 50 alloy heat treated between 450 and 650°C exhibits superior mechanical properties. We report the measurements of the ac core loss at various frequencies up to 4500 Hz of the Hiperco® 50 alloy samples annealed ...
    • Biological applications of multifunctional magnetic nanowires 

      Reich, D.H.; Tanase, M.; Hultgren, A.; Bauer, L.A.; Chen, C.S.; Meyer, G.J. (American Institute of Physics, 2003-05-15)
      Magnetic particles that can be bound to cells and biomolecules have become an important tool for the application of force in biology and biotechnology. Multifunctional magnetic nanowires fabricated by electrochemical ...
    • Cell manipulation using magnetic nanowires 

      Hultgren, A.; Tanase, M.; Chen, C.S.; Meyer, G.J.; Reich, D.H. (American Institute of Physics, 2003-05-15)
      The use of magnetic nanowires is demonstrated as a method for the application of force to mammalian cells. Magnetic separations were carried out on populations of NIH-3T3 mouse fibroblast cells using ferromagnetic Ni wires ...
    • Exchange coupling between Cr and ferromagnetic thin films 

      Yang, F.Y.; Chien, C.-L. (American Institute of Physics, 2003-05-15)
      Exchange bias has been observed in Ni81Fe19/Cr bilayers. The exchange bias field for Cr thickness tCr larger than 62 Å increases with tCr and levels off at tCr=150 Å, whereas coercivity increases without saturation. The ...
    • Quasi-Langmuir-Blodgett thin film deposition of carbon nanotubes 

      Gruner, G.; Gabriel, J.-C. P.; Armitage, N.P. (American Institute of Physics, 2004-03-15)
      The handling and manipulation of carbon nanotubes continues to be a challenge to those interested in the application potential of these promising materials. To this end, we have developed a method to deposit pure nonoriented ...