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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 ...

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 ...

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 ...

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 ...

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 ...

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. ...

Neutron scattering evidence for isolated spin-1/2 ladders in (C5D12N)2CuBr4

Nagler, S. E.; Pajerowski, D. M.; Meisel, M. W.; Broholm, C.; Schmidt, K. P.; Talham, D. R.; Brown, C.M.; Uhrig, G. S.; Savici, A.T.; Granroth, G. E. (American Physical Society, 2009-09-01)

Inelastic neutron scattering was used to determine the spin Hamiltonian for the singlet ground-state system of fully deuterated BPCB, (C5D12N)2CuBr4. A two-leg spin-1/2 ladder model, with J⊥=(1.09±0.01) meV and J∥=(0.296±0.005) ...

Field dependence of magnetic ordering in Kagome-staircase compound Ni3V2O8

Kenzelmann, M.; Harris, A. B.; Aharony, A.; Entin-Wohlman, O.; Yildirim, T.; Huang, Q.; Park, S.; Lawes, G.; Broholm, C.; Rogado, N.; Cava, R.J.; Kim, K. H.; Jorge, G.; Ramirez, A. P. (American Physical Society, 2006-07-01)

We present powder and single-crystal neutron diffraction and bulk measurements of the Kagome-staircase compound Ni3V2O8 (NVO) in fields up to 8.5 T applied along the c direction. (The Kagome plane is the a-c plane.) This ...

Phase diagram and spin Hamiltonian of weakly-coupled anisotropic S=½ chains in CuCl2·2((CD3)2SO)

Chen, Y.; Stone, M. B.; Kenzelmann, M.; Batista, C. D.; Reich, D.H.; Broholm, C. (American Physical Society, 2007-06-01)

Field-dependent specific heat and neutron scattering measurements were used to explore the antiferromagnetic S=½ chain compound CuCl2·2((CD3)2SO). At zero field the system acquires magnetic long-range order below TN=0.93 ...