| 1. |
- Boya, K., et al.
(författare)
-
Possible candidate for the realization of the floating phase in the S=5/2 frustrated spin-chain model : K3Fe(MoO4)2(Mo2O7 )
- 2024
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 109:15
-
Tidskriftsartikel (refereegranskat)abstract
- The frustrated spin-chain (FSC) systems exhibit exotic ground states and distinct quantum phase transitions. The ?=1/2 FSC is known to exhibit the Kosterlitz-Thouless transition from a commensurate gapless phase to a fully dimerized gapped phase upon the ratio of next-nearest-neighbor to nearest-neighbor coupling (?=?2/?1) being tuned. On the other hand, the ?=5/2 FSC system is known to show transitions from a commensurate gapless phase to partially dimerized and incommensurate floating phases [Chepiga, Affleck, and Mila, Phys. Rev. B 105, 174402 (2022)]. While a large region of the floating phase has been theoretically predicted for the ?=5/2 FSC model when ?>0.43, it is yet to be explored experimentally. Here, we have investigated a compound K3Fe(MoO4)2(Mo2O7), having well-separated ?=5/2 FSCs. The electronic structure calculations show that the ?=?2/?1 is close to 0.9, being similar to another FSC compound Bi3FeMo2O12 (?≈1.1). No magnetic long-range order is found down to 0.09 K, despite the relatively sizable Curie-Weiss temperature ???=−18K. The magnetic heat capacity shows the power-law behavior, indicating that the compound exhibits gapless excitations. Based on the experimental results and the theoretical calculations employed by density functional theory, we argue that the titled system is a possible candidate for exhibiting the floating phase.
|
|
| 2. |
- Kumar, Siddharth, et al.
(författare)
-
Electronic and magnetic structures of a mixed triple perovskite : Ba3NiRuIrO9
- 2024
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 110:2
-
Tidskriftsartikel (refereegranskat)abstract
- In search of spin-orbit coupling driven nonmagnetic J = 0 ground state and excitonic magnetism, various pentavalent iridates have been studied in recent years. However, a finite moment was observed in most of the cases due to solid state effects. In this work, we investigate the electronic and magnetic structure of 6H hexagonal compound Ba3NiRuIrO9, where Ir5+ is present along with magnetic Ni2+ and Ru5+ ions. Magnetic susceptibility measurements and neutron powder diffraction (NPD) experiments demonstrate the appearance of short-range magnetic ordering below 170 K and a long-range antiferromagnetic ordering below 80 K. The refinement of the NPD pattern further shows that the Ru and Ir moments interact antiferromagnetically within the dimer and interact ferromagnetically with the Ni sublattice. These experimental findings have been complemented by first-principles density functional theory calculations incorporating spin-orbit coupling effects and electronic correlations for the transitional metal d states. The computed magnetocrystalline anisotropy is also found to be significant and the crystallographic c axis comes out to be the easy axis of magnetization, consistent with the spin alignment direction found from NPD. This study shows that the mixed ruthenate iridate triple perovskite series is a promising family to study the interplay among spin-orbit coupling, electron correlation, and electron filling as a variety of Ba3MRuIrO9 with M as a transition metal ion, rare-earth ion, and alkali metal ions can be synthesized.
|
|
