43 research outputs found
NMR studies of the incommensurate helical antiferromagnet EuCo2P2 : determination of the antiferromagnetic propagation vector
Recently Ding et al. [Phys. Rev. B 95, 184404 (2017)] reported that their
nuclear magnetic resonance (NMR) study on EuCoAs successfully
characterized the antiferromagnetic (AFM) propagation vector of the
incommensurate helix AFM state, showing that NMR is a unique tool for
determination of the spin structures in incommensurate helical AFMs. Motivated
by this work, we have carried out Eu, P and Co NMR
measurements on the helical antiferromagnet EuCoP with an AFM ordering
temperature = 66.5 K. An incommensurate helical AFM structure was
clearly confirmed by Eu and P NMR spectra on single crystalline
EuCoP in zero magnetic field at 1.6 K and its external magnetic field
dependence. Furthermore, based on Co NMR data in both the paramagnetic
and the incommensurate AFM states, we have determined the model-independent
value of the AFM propagation vector k = (0, 0, 0.73 0.09)2/ where
is the -axis lattice parameter. The temperature dependence of k is also
discussed.Comment: 8 pages, 10 figures, accepted for publication in Phys. Rev. B. arXiv
admin note: substantial text overlap with arXiv:1704.0629
Helicity Selection of the Cycloidal Order in Noncentrosymmetric EuIrGe
The magnetic helicities of the cycloidal ordering in EuIrGe, with a
noncentrosymmetric tetragonal structure, have been studied by circularly
polarized resonant X-ray diffraction. It is shown that the helicity of each
cycloidal domain is uniquely determined and satisfies the symmetry relations of
the point group of the crystal structure. The result shows that the
cycloidal helicity is determined by the Dzyaloshinskii-Moriya type
antisymmetric exchange interaction. The domain selection and the phase
transition by the external magnetic field along [100] and [110] have also been
studied. It is shown that the cycloidal plane prefers to be perpendicular to
the field and the transverse conical state is realized.Comment: 6 pages, 4 figures, 5 figures in the supplemental material, accepted
for publication in J. Phys. Soc. Jp
Linear magnetoresistance in the low-field limit in density-wave materials
The magnetoresistance (MR) of a material is typically insensitive to
reversing the applied field direction and varies quadratically with magnetic
field in the low-field limit. Quantum effects [1], unusual topological band
structures [2], and inhomogeneities that lead to wandering current paths [3, 4]
can induce a crossover from quadratic to linear magnetoresistance with
increasing magnetic field. Here we explore a series of metallic charge- and
spin-density-wave systems that exhibit extremely large positive linear
magnetoresistance. By contrast to other linear MR mechanisms, this effect
remains robust down to miniscule magnetic fields of tens of Oersted at low
temperature. We frame an explanation of this phenomenon in a semi-classical
narrative for a broad category of materials with partially-gapped Fermi
surfaces due to density waves
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Linear magnetoresistance in the low-field limit in density-wave materials
The magnetoresistance (MR) of a material is typically insensitive to reversing the applied field direction and varies quadratically with magnetic field in the low-field limit. Quantum effects, unusual topological band structures, and inhomogeneities that lead to wandering current paths can induce a cross-over from quadratic to linear MR with increasing magnetic field. Here we explore a series of metallic charge- and spin-density-wave systems that exhibit extremely large positive linear MR. By contrast to other linear MR mechanisms, this effect remains robust down to miniscule magnetic fields of tens of Oersted at low temperature. We frame an explanation of this phenomenon in a semiclassical narrative for a broad category of materials with partially gapped Fermi surfaces due to density waves