Antiferromagnetic Order and Spin-Canting Transition in the Corrugated Square Net Compound Cu₃(TeO₄)(SO₄)·H₂O

Abstract

Strongly correlated electrons in layered perovskite structures have been the birthplace of high-temperature superconductivity, spin liquids, and quantum criticality. Specifically, the cuprate materials with layered structures made of cornersharing square-planar CuO 4 units have been intensely studied due to their Mott insulating ground state, which leads to high-temperature superconductivity upon doping. Identifying new compounds with similar lattice and electronic structures has become a challenge in solid-state chemistry. Here, we report the hydrothermal crystal growth of a new copper tellurite sulfate, Cu 3 (TeO 4 )(SO 4 )•H 2 O, a promising alternative to layered perovskites. The orthorhombic phase (space group Pnma) is made of corrugated layers of corner-sharing CuO 4 square-planar units that are edge-shared with TeO 4 units. The layers are linked by slabs of corner-sharing CuO 4 and SO 4 . Using both the bond valence sum analysis and magnetization data, we find purely Cu 2+ ions within the layers but a mixed valence of Cu 2+ /Cu + between the layers. Cu 3 (TeO 4 )(SO 4 )•H 2 O undergoes an antiferromagnetic transition at T N = 67 K marked by a peak in the magnetic susceptibility. Upon further cooling, a spin-canting transition occurs at T* = 12 K, evidenced by a kink in the heat capacity. The spin-canting transition is explained on the basis of a J 1 −J 2 model of magnetic interactions, which is consistent with the slightly different in-plane superexchange paths. We present Cu 3 (TeO 4 )(SO 4 )•H 2 O as a promising platform for the future doping and strain experiments that could tune the Mott insulating ground state into superconducting or spin liquid states.

Coupling of the Structure and Magnetism to Spin Splitting in Hybrid Organic–Inorganic Perovskites

“…Figure 1c displays such a M(H) loop taken at 10 K, confirming that there is a small canted AFM moment at low fields of ∼0.4 emu/g, with a coercive field of 0.25 T. When the applied magnetic field exceeds H SF ∼ 6.5 T, there is an increase in the magnetization characteristic of a spin-flop transition (Figure 1c). 40 This provides further evidence for the spincanted AFM order in [NH 2 NH 3 ]Co(HCOO) 3 . 26 The spincanted AFM behavior was also observed in Cu 3 (TeO 4 )(SO 4 )• H 2 O 40 and {Co(N 3 )(bpmb)(H 2 O) 2 •H 2 O} n .…”

“…From the Curie constant obtained through the fit ( C = 1.707 cm 3 K mol –1 ), an effective magnetic moment of μ eff ∼ 3.296 μ B /Co is obtained, using the relation C = N A μ B 2 μ eff 2 /3 k B . It is also worth noting from Figure b that there is a sudden decline in χ –1 at ∼15 K, signaling the characteristic of a spin-canted AFM system. − To confirm the occurrence of spin canting in [NH 2 NH 3 ]­Co­(HCOO) 3 , the magnetic field dependence of magnetization M ( H ) was measured at temperatures below the T N . Figure c displays such a M ( H ) loop taken at 10 K, confirming that there is a small canted AFM moment at low fields of ∼0.4 emu/g, with a coercive field of 0.25 T. When the applied magnetic field exceeds H SF ∼ 6.5 T, there is an increase in the magnetization characteristic of a spin-flop transition (Figure c) .…”

Evidence of Long-Range and Short-Range Magnetic Ordering in the Honeycomb Na3Mn2SbO6 Oxide

“…In the magnetic susceptibility recorded at 6 and 9 T, an increase in the susceptibility values is seen at higher temperatures (∼40 K). The upturn in the magnetic susceptibility below Neel temperature is also caused by canting of spins or a change of ordering (spin reorientation) Figure b demonstrates the magnetic susceptibility over the whole temperature range (300–2 K) measured at 1 T in which a broad maximum at 65 K remains intact while there is no sign of AFM ordering.…”

Two Purely Inorganic Cationic Tellurite Materials Based on Group IB Metal Tetrafluoroborates with Similar Lamellar Cationic Layers: [Cu2F(Te2O5)](BF4) and [Ag18O2(Te4O9)4(Te3O8)(BF4)2]·2HBF4

“…Energy-dispersive spectroscopy (EDS) measurements, which provide semiquantitative elemental analysis data, support the chemical formula (Figure S2). Both copper centers present a similar four coordinating environment with three oxygen atoms (O2, O3, and O4 i for Cu3 and O2, O4 i , and O5 i for Cu4, respectively) and one fluorine atom (F1 for Cu3 and F1 iii for Cu4, respectively), and the local environments of both copper sites can be described as the slightly distorted square planar of CuO 3 F with the interatomic distance of Cu–O and Cu–F ranging from 1.913(3) to 1.952(3) and from 1.912(3) to 1.939(3) Å, respectively, comparable with interatomic distance in most bivalent copper tellurites. − The sum of the bond valences (BVs) for both copper centers in compound 1 may be determined according to the BV model, and based on this model, the sum of all the BVs around any ion is equal to its ionic charge or valence. Here, the bond valence ( s ) is calculated as s = exp­[( r 0 – r )/ B ], where B = 0.37, with r 0 = 1.679, and 1.6 Å for Cu–O and Cu–F pairs, respectively .…”