Based on measurements of soft x-ray magnetic diffraction under in situ applied electric field, we report on significant manipulation and exciting of commensurate magnetic order in multiferroic ...ErMn2O5. The induced magnetic scattering intensity arises at the commensurate magnetic Bragg position whereas the initial magnetic signal almost persists. We demonstrate the possibility to imprint a magnetic response function in ErMn2O5 by applying an electric field.
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In MnSi the application of a small magnetic field destabilizes the helimagnetic order in a narrow temperature interval just below the helimagnetic ordering temperature and stabilizes the formation of ...a hexagonal lattice of skyrmions, i.e., a lattice composed of a type of magnetic vortex lines. We have studied the skyrmion lattice in MnSi using a cold triple-axis spectrometer. Our data suggests that the skyrmion lattice represents a three-dimensional spin structure. The collective spin excitations of the skyrmion lattice are strongly reminiscent of the rich spectrum of helimagnon bands, recently shown to be a universal property of the helimagnetic state of MnSi in zero magnetic field.
We report magnetization and specific heat measurements down to 2 K and electrical resistivity down to millikelvin temperatures on polycrystalline samples of the non-centrosymmetric compound Yb
2
Co
...12
P
7
. In addition to the previously reported ferromagnetic ordering of the cobalt sub-lattice at T
C
= 136 K we find a magnetic transition below T
M
= 5 K that is likely associated with ordering of the Yb ions. The broad nature of the specific heat anomaly suggests disordered magnetism and possible short-range correlations well above T
M
.
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Spherical neutron polarimetry with MuPAD Janoschek, M.; Klimko, S.; Gähler, R. ...
Physica. B, Condensed matter,
07/2007, Volume:
397, Issue:
1
Journal Article, Conference Proceeding
Peer reviewed
Over the last decade, the systematic application of spherical neutron polarmetry (SNP) has been successfully used to investigate scientific questions which were intractable before, e.g. study of ...magneto-electric crystals such as
LiCoPO
4
and
MnGeO
3
. Until now, the only device capable of performing routine SNP measurements at finite scattering angles was CryoPAD (cryogenic polarization analysis device), presented by Tasset et al. in 1989. Recently we demonstrated that an alternative setup named MuPAD (Mu-metal polarization analysis device) based on a zero-field environment produced by highly permeable mu-metal is also feasible. Here we present this new SNP device together with some first results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We characterize the properties of Ce1−xYbxRhIn5 single crystals with 0≤x≤1 using measurements of powder x-ray diffraction, energy dispersive x-ray spectroscopy, electrical resistivity, magnetic ...susceptibility, specific heat, x-ray absorption near edge structure (XANES), and neutron diffraction. The Yb valence vYb, calculated from the magnetic susceptibility and measured using XANES, decreases from 3+ at x=0 to ∼2.1+ at xact=0.2, where xact is the measured Yb concentration. A transition from incommensurate to commensurate antiferromagnetism is observed in neutron diffraction measurements along Q=(0.5,0.5,l) between 0.2≤xact≤0.27; this narrative is supported by specific-heat measurements in which a second robust feature appears at a temperature TI(TI<TN) for the same concentration range. Magnetic susceptibility measurements also reveal features which provide additional evidence of magnetic ordering. The results of this study suggest that the evolution of the Yb valence plays a critical role in tuning the magnetic ground state of Ce1−xYbxRhIn5.
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The ferroelectromagnet YMnO3 consists of weakly coupled triangular layers of S=2 spins. Below T(N) approximately equal to 70 K muon-spin relaxation data show two oscillatory relaxing signals due to ...magnetic order, with no purely relaxing signals resolvable (which would require different coexisting spin distributions). The transition temperature T(N) increases with applied hydrostatic pressure, even though the ordered moment decreases. These results suggest that pressure increases both the exchange coupling between the layers and the frustration within the layers.
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The 'Paul Scherrer Institut' (PSI,
http://www.psi.ch
) operates three major user laboratories for condensed-matter research on one campus: a third generation X-ray synchrotron source (SLS), the ...world's most powerful continuous-beam μSR facility (SμS) and the only continuous spallation neutron-source worldwide (SINQ).
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The noncentrosymmetric magnetic structure of ErMn2O5 has been shown to be very similar to that of HoMn2O5 (Vecchini et al 2008 Phys. Rev. B 77 134434). The magnetic modulation at 25 K has propagation ...vector and the symmetry imposes very few constraints on the magnetic configurations allowed. Only by combining the results of bulk magnetization measurements, powder and single crystal neutron diffraction and spherical neutron polarization analysis was it possible to distinguish clearly between different models. The susceptibility measurements show that the erbium magnetic moments are aligned parallel to the c-axis indicating strong single ion anisotropy. Spherical neutron polarimetry demonstrates the presence of two unequally populated chirality domains in ErMn2O5 single crystals. X-ray diffraction measurements on an ErMn2O5 powder using synchrotron radiation show that the buckling angles of the Mn-O-Mn bond change below the transition to the ferroelectric phase.
Quantum order in the chiral magnet MnSi Pfleiderer, C; Neubauer, A; Mühlbauer, S ...
Journal of physics. Condensed matter,
04/2009, Volume:
21, Issue:
16
Journal Article, Conference Proceeding
Peer reviewed
Systems lacking inversion symmetry, such as selected three-dimensional compounds, multilayers and surfaces support Dzyaloshinsky-Moriya (DM) spin-orbit interactions. In recent years DM interactions ...have attracted great interest, because they may stabilize magnetic structures with a unique chirality and non-trivial topology. The inherent coupling between the various properties provided by DM interactions is potentially relevant for a variety of applications including, for instance, multiferroic and spintronic devices. The, perhaps, most extensively studied material in which DM interactions are important is the cubic B20 compound MnSi. We review the magnetic field and pressure dependence of the magnetic properties of MnSi. At ambient pressure this material displays helical order. Under hydrostatic pressure a non-Fermi liquid state emerges, where a partial magnetic order, reminiscent of liquid crystals, is observed in a small pocket. Recent experiments strongly suggest that the non-Fermi liquid state is not due to quantum criticality. Instead it may be the signature of spin textures and spin excitations with a non-trivial topology.
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