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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. (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 ...

Anisotropic three-dimensional magnetism in CaFe2As2

McQueeney, R. J.; Diallo, S. O.; Antropov, V. P.; Samolyuk, G. D.; Broholm, C.; Ni, N.; Nandi, S.; Yethiraj, M.; Zaretsky, J.L.; Pulikkotil, J. J.; Kreyssig, A.; Lumsden, M.D.; Harmon, B. N.; Canfield, P.C. (American Physical Society, 2008-11-28)

Inelastic neutron scattering measurements of the magnetic excitations in CaFe2As2 indicate that the spin wave velocity in the Fe layers is exceptionally large and similar in magnitude to the cuprates. However, the spin ...

Neutron scattering from a coordination polymer quantum paramagnet

Hong, T.; Kenzelmann, M.; Turnbull, M. M.; Landee, C. P.; Lewis, B.D.; Schmidt, K. P.; Uhrig, G. S.; Broholm, C.; Reich, D. (American Physical Society, 2006-09-01)

Inelastic neutron scattering measurements are reported for a powder sample of the spin-1/2 quantum paramagnet Cu(quinoxaline)Br2. Magnetic neutron scattering is identified above an energy gap of 1.9 meV. Analysis of the ...

Quantum criticality in an organic magnet

Stone, M. B.; Broholm, C.; Reich, D.H.; Tchernyshyov, O.; Vorderwisch, P.; Harrison, N. (American Physical Society, 2006-06-30)

Exchange interactions between S=½ sites in piperazinium hexachlorodicuprate produce a frustrated bilayer magnet with a singlet ground state. We have determined the field-temperature phase diagram by high field magnetization ...

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 ...

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) ...

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. ...

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 ...

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 ...