Competings or frustrated interactions are common for condensed matter systems. In consideration of the effect of dipole–dipole interaction, the static properties of square lattice spin systems are investigated using ...Competings or frustrated interactions are common for condensed matter systems. In consideration of the effect of dipole–dipole interaction, the static properties of square lattice spin systems are investigated using the Wang–Landau algorithm. The dynamic hysteresis is also simulated using the Monte Carlo(MC) method. The step-like magnetization under a DC magnetic field and two distinct peaks in hysteresis dispersion under an AC magnetic field are observed. Then, the formation of the properties of the frustrated dipolar array are discussed.展开更多
In this paper, the dilution effects of non-magnetic Y ions on spin-ice compound Dy_2Ti_2O_7 by infrared and Raman spectra and magnetization measurements were investigated. An anomalous phonon softening with temperatur...In this paper, the dilution effects of non-magnetic Y ions on spin-ice compound Dy_2Ti_2O_7 by infrared and Raman spectra and magnetization measurements were investigated. An anomalous phonon softening with temperature decreasing is found in both the parent and diluted compounds, and Y doping can relax the softening of phonons except that of the IR mode near 233 cm^-1, indicating a strong phonon–phonon coupling in the spin-ice material.The magnetization measurements reveal that the nonmagnetic impurities do not severely influence the spin-ice rules in the ground state when the level of dilution is not very high. However, a large amount of dilution enhance the disorder and break the spin-ice state because the collective spin-flip clusters are no longer available.展开更多
Three-dimensional(3D)nanostructured functional materials are important systems allowing new means for intricate control of electromagnetic properties.A key problem is realising a 3D printing methodology on the nanosca...Three-dimensional(3D)nanostructured functional materials are important systems allowing new means for intricate control of electromagnetic properties.A key problem is realising a 3D printing methodology on the nanoscale that can yield a range of functional materials.In this article,it is shown that two-photon lithography,when combined with laser ablation of sacrificial layers,can be used to realise such a vision and produce 3D functional nanomaterials of complex geometry.Proof-of-principle is first shown by fabricating planar magnetic nanowires raised above the substrate that exhibit controlled domain wall injection and propagation.Secondly,3D artificial spin-ice(3DASI)structures are fabricated,whose complex switching can be probed using optical magnetometry.We show that by careful analysis of the magneto-optical Kerr effect signal and by comparison with micromagnetic simulations,depth dependent switching information can be obtained from the 3DASI lattice.The work paves the way for new materials,which exploit additional physics provided by non-trivial 3D geometries.展开更多
文摘Competings or frustrated interactions are common for condensed matter systems. In consideration of the effect of dipole–dipole interaction, the static properties of square lattice spin systems are investigated using the Wang–Landau algorithm. The dynamic hysteresis is also simulated using the Monte Carlo(MC) method. The step-like magnetization under a DC magnetic field and two distinct peaks in hysteresis dispersion under an AC magnetic field are observed. Then, the formation of the properties of the frustrated dipolar array are discussed.
基金financially supported by the State Key Project of Fundamental Research of China (Nos. 2010CB923403 and 2011CBA00111)the National Natural Science Foundation of China (Nos. 11174290 and U1232142)the Hundred Talents Program of the Chinese Academy of Sciences (No. 2010A1175)
文摘In this paper, the dilution effects of non-magnetic Y ions on spin-ice compound Dy_2Ti_2O_7 by infrared and Raman spectra and magnetization measurements were investigated. An anomalous phonon softening with temperature decreasing is found in both the parent and diluted compounds, and Y doping can relax the softening of phonons except that of the IR mode near 233 cm^-1, indicating a strong phonon–phonon coupling in the spin-ice material.The magnetization measurements reveal that the nonmagnetic impurities do not severely influence the spin-ice rules in the ground state when the level of dilution is not very high. However, a large amount of dilution enhance the disorder and break the spin-ice state because the collective spin-flip clusters are no longer available.
基金S.L.acknowledges funding from the Engineering and Physics Research Council(EP/R009147/1)from the Leverhulme Trust(RPG-2021-139).
文摘Three-dimensional(3D)nanostructured functional materials are important systems allowing new means for intricate control of electromagnetic properties.A key problem is realising a 3D printing methodology on the nanoscale that can yield a range of functional materials.In this article,it is shown that two-photon lithography,when combined with laser ablation of sacrificial layers,can be used to realise such a vision and produce 3D functional nanomaterials of complex geometry.Proof-of-principle is first shown by fabricating planar magnetic nanowires raised above the substrate that exhibit controlled domain wall injection and propagation.Secondly,3D artificial spin-ice(3DASI)structures are fabricated,whose complex switching can be probed using optical magnetometry.We show that by careful analysis of the magneto-optical Kerr effect signal and by comparison with micromagnetic simulations,depth dependent switching information can be obtained from the 3DASI lattice.The work paves the way for new materials,which exploit additional physics provided by non-trivial 3D geometries.
