Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMagnetism of Nd$_2$O$_3$ single crystals near the N{e}el temperature
121
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Single crystals of Nd$_2$O$_3$ were grown and characterized using neutron scattering and thermodynamic measurements. Nd$_2$O$_3$ has long-range antiferromagnetic order below $T_{rm N}$ = 0.55 K and specific heat measurements have demonstrated that a significant amount of the magnetic entropy is released above $T_{rm N}$. Inelastic neutron scattering experiments reveal a magnetic mode(s) with little dispersion peaked at $approx$ 0.37 meV that is of greatest intensity below $T_{rm N}$ but persists above 2$T_{rm N}$. This persistence of dynamic correlations is likely related to frustrated interactions associated with the nearly-ideal stacked triangular lattice geometry of $J_{textrm{eff}}$ = 1/2 spins on Nd$^{3+}$ ions. The magnetization is observed to be strongly anisotropic at all temperatures due to crystal field effects, with easy-plane anisotropy observed. A non-compensated magnetic structure is inferred from the temperature-dependence of the magnetization when a magnetic field of sufficient strength is applied within the basal plane near $T_{rm N}$, and the evolution of the long-range order is summarized in a temperature-field phase diagram.
rate research
Read More
We have studied the physical properties of Nd$_2$O$_3$ with neutron diffraction, inelastic neutron scattering, heat capacity, and magnetic susceptibility measurements. Nd$_2$O$_3$ crystallizes in a trigonal structure, with Nd$^{3+}$ ions surrounded by cages of 7 oxygen anions. The crystal field spectrum consists of four excitations spanning the energy range 3-60 meV. The refined eigenfunctions indicate XY-spins in the $ab$ plane. The Curie-Weiss temperature of $theta_{CW}=-23.7(1)$ K was determined from magnetic susceptibility measurements. Heat capacity measurements show a sharp peak at 550 mK and a broader feature centered near 1.5 K. Neutron diffraction measurements show that the 550 mK transition corresponds to long-range anti-ferromagnetic order implying a frustration index of $theta_{CW}/T_Napprox43$. These results indicate that Nd$_2$O$_3$ is a structurally and chemically simple model system for frustration caused by competing interactions with moments with predominate XY anisotropy.
Neutron elastic scattering experiments have been performed on the spin gap system TlCuCl$_3$ in magnetic fields parallel to the $b$-axis. The magnetic Bragg peaks which indicate the field-induced N{e}el ordering were observed for magnetic field higher than the gap field $H_{rm g}approx 5.5$ T at $Q=(h, 0, l)$ with odd $l$ in the $a^*-c^*$ plane. The spin structure in the ordered phase was determined. The temperature and field dependence of the Bragg peak intensities and the phase boundary obtained were discussed in connection with a recent theory which describes the field-induced N{e}el ordering as a Bose-Einstein condensation of magnons.
We present an investigation of the influence of low-levels of chemical substitution on the magnetic ground state and N{ e}el skyrmion lattice (SkL) state in GaV$_4$S$_{8-y}$Se$_y$, where $y =0, 0.1, 7.9$, and $8$. Muon-spin spectroscopy ($mu$SR) measurements on $y=0$ and 0.1 materials reveal the magnetic ground state consists of microscopically coexisting incommensurate cycloidal and ferromagnetic environments, while chemical substitution leads to the growth of localized regions of increased spin density. $mu$SR measurements of emergent low-frequency skyrmion dynamics show that the SkL exists under low-levels of substitution at both ends of the series. Skyrmionic excitations persist to temperatures below the equilibrium SkL in substituted samples, suggesting the presence of skyrmion precursors over a wide range of temperatures.
Neutron diffraction and magnetic susceptibility studies of orthorhombic single crystal {Ksub} confirm the three dimensional (3D) C-type antiferromagnetic (AFM) ordering of the Mn$^{2+}$ moments at $T_{rm N}=305 pm 3$ K which is slightly higher than that of the parent SrMnSb$_2$ with $T_{rm N}=297 pm 3$ K. Susceptibility measurements of the K-doped and parent crystals above $T_{rm N}$ are characteristic of 2D AFM systems. This is consistent with high temperature neutron diffraction of the parent compound that display persisting 2D AFM correlations well above $T_{rm N}$ to at least $sim 560$ K with no evidence of a ferromagnetic phase. Analysis of the de Haas van Alphen magnetic oscillations of the K-doped crystal is consistent with hole doping.
We present results for the phase diagram of an SU($N$) generalization of the Heisenberg antiferromagnet on a bipartite three-dimensional anisotropic cubic (tetragonal) lattice as a function of $N$ and the lattice anisotropy $gamma$. In the isotropic $gamma=1$ cubic limit, we find a transition from N{e}el to valence bond solid (VBS) between N=9 and N=10. We follow the N{e}el-VBS transition to the limiting cases of $gamma ll 1 $ (weakly coupled layers) and $gamma gg 1$ (weakly coupled chains). Throughout the phase diagram we find a direct first-order transition from N{e}el at small-$N$ to VBS at large-$N$. In the three-dimensional models studied here, we find no evidence for either an intervening spin-liquid photon phase or a continuous transition, even close to the limit $gamma ll 1$ where the isolated layers undergo continuous N{e}el-VBS transitions.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
