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On the basis of first principles density functional theory electronic structure calculations as well as classical spin analysis, we explored why the magnetic oxide Li2CuO2, consisting of CuO2 ribbon chains made up of edge-sharing CuO4 squares, does not exhibit a spiral-magnetic order. Our work shows that, due to the next-nearest-neighbor interchain interactions, the observed collinear magnetic structure becomes only slightly less stable than the spin-spiral ground state, and many states become nearly degenerate in energy with the observed collinear structure. This suggests that the collinear magnetic structure of Li2CuO2 is a consequence of order-by-disorder induced by next-nearest-neighbor interchain interactions.
The S=2 anisotropic triangular lattice alpha-NaMnO2 is studied by neutron inelastic scattering. Antiferromagnetic order occurs at T ~ 45 K with opening of a spin gap. The spectral weight of the magnetic dynamics above the gap (Delta ~ 7.5 meV) has be
The origin of the spiral spin-order in perovskite multiferroic manganites $R$MnO$_{3}$ ($RE=$ Tb or Dy) is here investigated using a two $e_{rm g}$-orbitals double-exchange model. Our main result is that the experimentally observed spiral phase can b
We have discovered a novel candidate for a spin liquid state in a ruthenium oxide composed of dimers of $S = $ 3/2 spins of Ru$^{5+}$,Ba$_3$ZnRu$_2$O$_9$. This compound lacks a long range order down to 37 mK, which is a temperature 5000-times lower t
We have prepared magnetic graphite samples bombarded by protons at low temperatures and low fluences to attenuate the large thermal annealing produced during irradiation. An overall optimization of sample handling allowed us to find Curie temperature
The dynamical properties of free and bound domain-wall excitations in Ising-chain materials have recently become the focus of intense research interest. New materials and spectrometers have made it possible to control the environment of coupled Ising