Sources of magnetic fields-magnetic monopoles-have so far proven elusive as elementary particles. Condensed-matter physicists have recently proposed several scenarios of emergent quasiparticles ...resembling monopoles. A particularly simple proposition pertains to spin ice on the highly frustrated pyrochlore lattice. The spin-ice state is argued to be well described by networks of aligned dipoles resembling solenoidal tubes-classical, and observable, versions of a Dirac string. Where these tubes end, the resulting defects look like magnetic monopoles. We demonstrated, by diffuse neutron scattering, the presence of such strings in the spin ice dysprosium titanate (Dy2Ti2O7). This is achieved by applying a symmetry-breaking magnetic field with which we can manipulate the density and orientation of the strings. In turn, heat capacity is described by a gas of magnetic monopoles interacting via a magnetic Coulomb interaction.
By using bulk magnetization, electron spin resonance (ESR), heat capacity, and neutron scattering techniques, we characterize the thermodynamic and quantum phase diagrams of Ba3Cr2O8. Our ESR ...measurements indicate that the low field paramagnetic ground state is a mixed state of the singlet and the Sz=0 triplet for H perpendicular c. This suggests the presence of an intradimer Dzyaloshinsky-Moriya (DM) interaction with a DM vector perpendicular to the c axis.
Magnetic structure of TmCu2Ge2 Penc, B.; Gerischer, S.; Hoser, A. ...
Journal of magnetism and magnetic materials,
03/2012, Volume:
324, Issue:
5
Journal Article
Peer reviewed
TmCu2Ge2 compound crystallizes in the tetragonal ThCr2Si2-type crystal structure. The neutron diffraction reveals the presence of an incommensurate antiferromagnetic order below TN=2.5K. The Tm ...magnetic moment of 5.0(1)μB at 0.47K is parallel to the c-axis. The order is described by the propagation vector k=kx, kx, 0, where kx=0.117(3). The increase of the values of the components kx near the Néel temperature is observed.
▸ Neutron diffraction measurements at low temperature (T=0.47K) of TmCu2Ge2 compound indicate incommensurate antiferromagnetic structure described by the propagation vector k=kx, kx, 0, where kx=0.117(3). ▸ Magnetic structure is stable in temperature region T=0.47K to TN=2.5K. ▸ Properties of TmCu2Ge2 compound result from interactions of RKKY type and Crystal Electric Field.
We report a high-field-induced magnetic phase in a single crystal of U(Ru0.92Rh0.08)2Si2. Our neutron study, combined with high-field magnetization, shows that the magnetic phase above the first ...metamagnetic transition at μ0Hc1=21.6 T has an uncompensated commensurate antiferromagnetic structure with a propagation vector Q2=2300 possessing two single-Q domains. U moments of 1.45(9)μB directed along the c axis are arranged in an up-up-down sequence propagating along the a axis, in agreement with bulk measurements. The U magnetic form factor at high fields is consistent with both the U3+ and U4+ types. The low-field short-range order that emerges from pure URu2Si2 due to Rh doping is initially strengthened by the field but disappears in the field-induced phase. The tetragonal symmetry is preserved across the transition, but the a-axis lattice parameter increases already at low fields. Our results are in agreement with an itinerant electron model with 5f states forming bands pinned in the vicinity of the Fermi surface that is significantly reconstructed by the applied magnetic field.
Sources of magnetic fields--magnetic monopoles--have so far proven elusive as elementary particles. Condensed-matter physicists have recently proposed several scenarios of emergent quasiparticles ...resembling monopoles. A particularly simple proposition pertains to spin ice on the highly frustrated pyrochlore lattice. The spin-ice state is argued to be well described by networks of aligned dipoles resembling solenoidal tubes--classical, and observable, versions of a Dirac string. Where these tubes end, the resulting defects look like magnetic monopoles. We demonstrated, by diffuse neutron scattering, the presence of such strings in the spin ice dysprosium titanate (Dy₂Ti₂O₇). This is achieved by applying a symmetry-breaking magnetic field with which we can manipulate the density and orientation of the strings. In turn, heat capacity is described by a gas of magnetic monopoles interacting via a magnetic Coulomb interaction.
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