Now showing items 1-13 of 13

    • Asymmetric domain nucleation and unusual magnetization reversal in ultrathin Co films with perpendicular anisotropy 

      Iunin, Y.L.; Kabanov, Y.P.; Nikitenko, V.I.; Cheng, X.M.; Clarke, D.; Tretiakov, O.A.; Tchernyshyov, O.; Shapiro, A.J.; Shull, R.D.; Chien, C.L. (American Physical Society, 2007-03-16)
      We report unexpected phenomena during magnetization reversal in ultrathin Co films and Co/Pt multilayers with perpendicular anisotropy. Using magneto-optical Kerr microscopy and magnetic force microscopy we have observed ...
    • Broken parity and a chiral ground state in the frustrated magnet CdCr2O4 

      Chern, G.-W.; Fennie, C.J.; Tchernyshyov, O. (American Physical Society, 2006-08-01)
      We present a model describing the lattice distortion and incommensurate magnetic order in the spinel CdCr2O4, a good realization of the Heisenberg 'pyrochlore' antiferromagnet. The magnetic frustration is relieved through ...
    • Composite domain walls in flat nanomagnets: the magnetostatic limit 

      Youk, H.; Chern, G.-W.; Merit, K.; Oppenheimer, B.; Tchernyshyov, O. (American Institute of Physics, 2006-04-15)
      We discuss the structure of the so-called 'vortex' domain walls in soft magnetic nanoparticles. A wall of this kind is a composite object consisting of three elementary topological defects: two edge defects with winding ...
    • Condensation of magnons and spinons in a frustrated ladder 

      Fouet, J.-B.; Mila, F.; Clarke, D.; Youk, H.; Tchernyshyov, O.; Fendley, P.; Noack, R.M. (American Physical Society, 2006-06-01)
      Motivated by the ever-increasing experimental effort devoted to the properties of frustrated quantum magnets in a magnetic field, we present a careful and detailed theoretical analysis of a one-dimensional version of this ...
    • Dynamics of a vortex domain wall in a magnetic nanostrip: application of the collective-coordinate approach 

      Clarke, D.J.; Tretiakov, O.A.; Chern, G.-W.; Bazaliy, Ya.B.; Tchernyshyov, O. (American Physical Society, 2008-10-01)
      The motion of a vortex domain wall in a ferromagnetic strip of submicron width under the influence of an external magnetic field exhibits three distinct dynamical regimes. In a viscous regime at low fields the wall moves ...
    • Dynamics of domain walls in magnetic nanostrips 

      Tretiakov, O.A.; Clarke, D.; Chern, G.-W.; Bazaliy, Ya.B.; Tchernyshyov, O. (American Physical Society, 2008-03-28)
      We express the dynamics of domain walls in ferromagnetic nanowires in terms of collective coordinates, generalizing Thiele[psila]s steady-state results. For weak external perturbations the dynamics is dominated by a few ...
    • Fermionic spin excitations in two- and three-dimensional antiferromagnets 

      Zhihao, Hao; Tchernyshyov, O. (American Physical Society, 2009-10-30)
      Spin excitations in an ordered Heisenberg magnet are magnons-bosons with spin 1. That may change when frustration and quantum fluctuations suppress the order and restore the spin-rotation symmetry. We show that spin ...
    • Ising phases of Heisenberg ladders in a magnetic field 

      Penc, K.; Fouet, J.-B.; Miyahara, S.; Tchernyshyov, O.; Mila, F. (American Physical Society, 2007-09-14)
      We show that Dzyaloshinskii-Moriya (DM) interactions can substantially modify the phase diagram of spin-1/2 Heisenberg ladders in a magnetic field provided they compete with exchange. For nonfrustrated ladders, they induce ...
    • Partial order from disorder in a classical pyrochlore antiferromagnet 

      Chern, G.-W.; Moessner, R.; Tchernyshyov, O. (American Physical Society, 2008-10-01)
      We investigate theoretically the phase diagram of a classical Heisenberg antiferromagnet on the pyrochlore lattice perturbed by a weak second-neighbor interaction J2. The huge ground-state degeneracy of the nearest-neighbor ...
    • 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 ...
    • Stripes in thin ferromagnetic films with out-of-plane anisotropy 

      Clarke, D.; Tretiakov, O.A.; Tchernyshyov, O. (American Physical Society, 2007-05-01)
      We examine the T=0 phase diagram of a thin ferromagnetic film with a strong out-of-plane anisotropy (e.g., Co/Pt multilayers) in the vicinity of the reorientation phase transition. The phase diagram in the anisotropy-applied-field ...
    • Topological defects in flat nanomagnets: the magnetostatic limit 

      Chern, G.-W.; Youk, H.; Tchernyshyov, O. (American Institute of Physics, 2006-04-15)
      We discuss elementary topological defects in soft magnetic nanoparticles in the thin-film geometry. In the limit dominated by magnetostatic forces the low-energy defects are vortices (winding number n=+1), cross ties (n=-1), ...
    • Wrinkling of a bilayer membrane 

      Concha, A.; McIver, J.W.; Mellado, P.; Clarke, D.; Tchernyshyov, O.; Leheny, R.L. (American Physical Society, 2007-01)
      The buckling of elastic bodies is a common phenomenon in the mechanics of solids. Wrinkling of membranes can often be interpreted as buckling under constraints that prohibit large-amplitude deformation. We present a ...