Low-temperature excitations in a dilute three-dimensional anisotropic antiferromagnet

Ordered magnetism in the intrinsically decorated jeff=12α−CoV3O8

“…Such behavior is suggestive that hydrodynamic and long wavelength fluctuations are not strongly sensitive to the disorder in α-CoV 3 O 8 , in contrast with expectations based on theory 173,174 . The robust nature of the dynamics to dilution, and in particular disorder is analogous to several observations in dilute random field magnets and in particular the Fe x Zn 1−x F 2 series 46,175,176 , where sharp excitations are still observable for large amount of doping 49 . Unlike members of the Fe x Zn 1−x F 2 series closer to the percolation threshold (x p ∼ 0.24) that exhibit spin glass behavior 6,45,49,170 , Fe 0.5 Zn 0.5 F 2 assumes long range antiferromagnetic order in zero field with a T N corresponding to half of that of FeF 2 177,178 .…”

“…However, an alternative explanation may lie in the intrinsic cationic disorder inherent to the disordered Ibam structure of α-CoV 3 O 8 52 . Such large cationic disorder would result in a distribution of cationic sites and correspondingly a spread of spinorbit transitions as has been shown for multiple doped systems 46,49,[112][113][114][115][116] , and thus perhaps such disorder may also explain the large bandwidth in α-CoV 3 O 8 due to a distribution of molecular fields splitting the j eff = 1 2 manifold. We investigate this possibility in this section using scaling.…”

“…In contrast to the disordered systems described above, where the disorder is a consequence of an addition external to the original system (e.g. doping 6,[44][45][46][47][48] , porous media 32,37,38 , etc. ), and thus can be finely tuned 54 , the disorder in α-CoV 3 O 8 is simply inherent to its Ibam crystal structure.…”

Neutron scattering experiments and simulations near the magnetic percolation threshold ofFexZn1−xF2Álvarez1, Aso2, Belanger3 et al. 2012Phys. Rev. B1020View full textAdd to dashboardCite

“…Similar results were found in far-infrared absorption experiments, high magnetic field pulsed laser absorption, and inelastic neutron scattering experiments for x 0.4. [14][15][16] It was observed in the pulsed laser absorption measurements that the peaks become more easily resolvable for x = 0.4 and that for this case the simplistic modeling described above proves wholly inadequate; 16 the spacings of the resolved peaks do not correspond to the simple model. The excitations were found to be largely localized, having little dispersion.…”

“…19,20 There is limited information about the effect of dilution on the anisotropy, but it also does not appear to vary by a large amount. 20 Magnetic ordering in Fe x Zn 1−x F 2 has been experimentally studied previously [14][15][16][21][22][23][24][25][26][27][28][29] at magnetic concentrations x equal to or near x p = 0.246, the magnetic percolation threshold for the body-centered tetragonal magnetic structure with an interaction between the body-centered and corner ions (J 2 in Fe x Zn 1−x F 2 ). The H = 0 random-exchange transition should be expected for x > x p if there is only the dominant exchange interaction J 2 .…”