Na + Redistribution by Electrochemical Na + /K + Exchange in Layered Na x Ni 2 SbO 6
Abstract not provided
Kim, Haegyeom↗
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High-temperature X-ray diffraction measurements of fluorite-related rare earth antimonates Ln{sub 3}SbO{sub 7} (Ln=Nd, Tb) and their magnetic properties
Ternary rare-earth antimonates Ln{sub 3}SbO{sub 7} (Ln=rare earths) were prepared, and their structures were determined by X-ray diffraction measurements. They crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln=La, Pr; Ccmm for Ln=Sm–Dy), in which Ln{sup 3+} ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated). For Ln=Nd, two phases with the Cmcm and Ccmm space groups coexist at room temperature. When the temperature was increased, the Nd{sub 3}SbO{sub 7} compound transformed into a single phase with the space group Cmcm. Through magnetic susceptibility measurements, an antiferromagnetic transition was observed at 3.0 K (Ln=Nd) and 7.8 K (Ln=Tb). Analysis of the magnetic specific heat for Tb{sub 3}SbO{sub 7} indicates that the 8-coordinated Tb ions magnetically orders at 7.8 K, and with furthermore decreasing temperature, the 7-coordinated Tb ions shows antiferromagnetic ordering at 3.0 K. - Graphical abstract: Temperature dependence of the specific heat divided by temperature (C{sub p}/T) and the magnetic entropy (S{sub mag}) for Tb{sub 3}SbO{sub 7}. Two-step magnetic transition has been observed. - Highlights: • The phase transition of Nd{sub 3}SbO{sub 7} is from the Ccmm space group to the Cmcm one. • Nd{sub 3}SbO{sub 7} shows an antiferromagnetic transition at 3.0 K. • For Tb{sub 3}SbO{sub 7}, two-step magnetic transition has been observed at 7.8 and 3.0 K.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Magnetic order in single crystals of Na 3 Co 2 SbO 6 with a honeycomb arrangement of 3d 7 Co 2+ ions
We have synthesized single crystals of Na 3 Co 2 SbO 6 and characterized the structure and magnetic order by measuring anisotropic magnetic properties, heat capacity, and x-ray and neutron single crystal diffraction. Magnetic properties and specific heat of polycrystalline Na 3 Co 2 SbO 6 were also measured for comparison. Na 3 Co 2 SbO 6 crystallizes in a monoclinic structure (space group C 2 / m ) with [Co 2 SbO 6 ] 3- layers separated by Na + ions. The temperature dependence of magnetic susceptibility shows significant anisotropic behavior in the whole temperature range 2–350 K investigated in this work. An effective moment of about 5.5μ B /Co 2+ from a Curie-Weiss fitting of the magnetic susceptibility is larger than the spin only value and signals significant orbital contribution. Na 3 Co 2 SbO 6 single crystal undergoes a transition into a long-range antiferromagnetically ordered state below T N = 5K. Neutron single crystal diffraction confirmed the zigzag magnetic structure with a propagation vector k = (0.5,0.5,0). The ordered moment is found to be 0.9 μ B at 4 K and align along the crystallographic b axis. Density functional theory calculations suggest that the experimentally observed zigzag order is energetically competing with the Néel order. Furthermore, it is also found that the covalency between Co d and O p is quite strong and competes with the local spin-orbit coupling, suggesting a J eff = 1/2 ground state may not be realized in this compound.
36 MATERIALS SCIENCE↗
Impact of structural distortions on the correlated electronic structure of orbital-selective Mott insulating Na 3 Co 2 SbO 6 under strain
Na 3 Co 2 SbO 6 is a promising candidate to realize the Kitaev spin liquid phase since the large Kitaev spin exchange interaction is tunable via the change in electronic structure, such as the trigonal crystal field splitting (Δ TCF ). Here, in this study, we show that the uncorrelated electronic structure of Na 3 Co 2 SbO 6 is rather insensitive to the strain effect due to the low crystal symmetry accompanied by oxygen displacements and the presence of Sb s orbitals. Using density functional theory plus dynamical mean field theory, we find that the correlated electronic structure of Na 3 Co 2 SbO 6 is an orbital-selective Mott insulating state where the trigonal a 1g orbital is insulating due to the nearly full occupation, while other d orbitals behave as typical Mott insulators, resulting in the effective tunability of Δ TCF under the strain effect. The sign change of Δ TCF can occur as the in-plane tensile strain is applied, and the Kitaev spin liquid phase could possibly be realized due to the strongly suppressed Δ TCF under tensile strain. Our results show that the local Co-site symmetry and dynamical correlation effects will play an important role in engineering the novel magnetic phase in this and related materials.
Nguyen, Nam [Univ. of Illinois, Chicago, IL (Unite↗
Anomalous Ferromagnetic Behavior in Orthorhombic Li 3 Co 2 SbO 6
Monoclinic Li 3 Co 2 SbO 6 has been proposed as a Kitaev spin liquid candidate and investigated intensively, whereas the properties of its polymorph, the orthorhombic phase, are less known. In this work, we report the magnetic properties of orthorhombic Li 3 Co 2 SbO 6 as revealed by dc and ac magnetic susceptibility, muon spin relaxation (μSR), and neutron diffraction measurements. Successive magnetic transitions at 115, 89, and 71 K were observed in the low-field dc susceptibility measurements. The transitions below T N (115 K) are suppressed at higher applied fields. However, zero-field ac susceptibility measurements reveal distinct frequency-independent transitions at about 114, 107, 97, 79, and 71 K. A long-range magnetic ordered state was confirmed by specific heat, μSR, and neutron diffraction measurements, all indicating a single transition at about 115 K. The discrepancy between different measurements is attributed to possible stacking faults and/or local disorders of the ferromagnetic zigzag chains, resulting in ferromagnetic boundaries within the overall antiferromagnetic matrix.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Evidence of Long-Range and Short-Range Magnetic Ordering in the Honeycomb Na 3 Mn 2 SbO 6 Oxide
We present a comprehensive study of the synthesis, structure, and magnetic properties of the honeycomb oxide Na 3 Mn 2 SbO 6 supported by neutron diffraction, heat capacity, and magnetization measurements. The refinements of the neutron diffraction patterns (150, 50, and 45 K) using the Rietveld method confirm the monoclinic (S. G. C2/m) structure. Temperature-dependent magnetic susceptibilities measured at varying fields along with the heat capacity measurements demonstrate the coexistence of long-range ordering (∼42 K) and short-range ordering (∼65 K). The field-dependent isothermal magnetization measurements at 5 K indicate a spin-flop transition around 5 T. Rietveld refinements of the low-temperature (below 45 K) neutron diffraction data further confirm the long-range magnetic ordering. In addition, the temperature variation of the lattice parameters obtained from the neutron powder diffraction analysis exhibited a distinct anomaly near the antiferromagnetic transition temperature. The appearance of the concomitant broadened backgrounds in the neutron powder diffraction data collected at 80, 50, and 45 K supports the short-range ordering. The resultant magnetic structure consists of spins that are aligned antiparallel with the nearest neighbors and also with the spins of the adjacent honeycomb layers. The occurrence of a fully ordered magnetic ground state (Neel antiferromagnetic (AFM)) in Na3Mn 2 SbO 6 consolidates the significance of fabricating new honeycomb oxides.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
In-plane multi-q magnetic ground state of Na 3 Co 2 SbO 6
We report Na 3 Co 2 SbO 6 is a potential Kitaev magnet with a monoclinic layered crystal structure. Recent investigations of the C3-symmetric sister compound Na 2 Co 2 TeO 6 have uncovered a unique triple-q magnetic ground state, as opposed to a single-q (zigzag) one, prompting us to examine the influence of the reduced structural symmetry of Na 3 Co 2 SbO 6 on its ground state. Neutron diffraction data obtained on a twin-free crystal reveal that the ground state remains a multi-q state, despite the system's strong non-C 3 -symmetric anisotropy. This robustness of multi-q orders suggests that they are driven by a common mechanism in the honeycomb cobaltates, such as interactions beyond the bilinear order. Spin-polarized neutron diffraction results show that the ordered moments are entirely in plane, with each staggered component orthogonal to the propagating wave vector. The inferred ground state appears more compatible with the so-called XXZ easy-plane anisotropy than the Kitaev anisotropy, and features unequal ordered moments reduced by strong quantum fluctuations.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Systems Engineering (SE) Approach of Developing A Passive Safety Injection System (PSIS) to Cope with APR1400 Extended Station Black-Out (SBO) Accident Using RELAP5
On 11 March 2011 the power supply and cooling of the three Fukushima Daiichi reactors were disabled by a major earthquake followed by a relatively high tsunami waves. The earthquake damaged the electrical grid which is the normal power supply for the reactors, then the tsunami waves disabled the emergency diesel generators of the Fukushima Daiichi reactors, which left the plant with no alternating current (AC) source. This condition is called 'Station Black-Out'. The reactors were tripped immediately, but due to the nuclear physics phenomena, the reactor cores were still producing thermal power, which is generated by the decay of radioactive fission products in the reactor core, known as decay heat. The decay heat had not been circulated to an external heat sink and eventually the accumulative heat produced in the core led to damage to the reactor cores. After the Fukushima Daiichi accident, Design Extension Condition (DEC) such as total loss of feed water (TLOFW), and prolonged Station Black-Out (SBO) attracted the attention of nuclear experts. The attention focuses on the defense in depth concept, redundancy and sustainability of the systems, and development of the passive safety systems, which rely on natural physics laws. The topic of this paper is to discuss the possibility of attaching a Passive Safety Injection System (PSIS) to the APR1400. The PSIS is a safety system which provides adequate cooling water to the steam generators after the loss of the Auxiliary Feed Water System (AFWS) during an extended SBO accident. The PSIS will be available while the power supply of the plant is being recovered and the active safety systems take over the functionality. The anticipated PSIS will be automatically actuated to enhance the engineered safety feature and to reduce the human errors. (authors)
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Materials Data on Ba2Mn3(SbO)2 by Materials Project
Ba2Mn3(SbO)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba2+ is bonded in a 4-coordinate geometry to four equivalent Sb3- and four equivalent O2- atoms. All Ba–Sb bond lengths are 3.65 Å. All Ba–O bond lengths are 2.83 Å. There are two inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded in a square co-planar geometry to two equivalent Sb3- and four equivalent O2- atoms. Both Mn–Sb bond lengths are 3.56 Å. All Mn–O bond lengths are 2.23 Å. In the second Mn2+ site, Mn2+ is bonded to four equivalent Sb3- atoms to form a mixture of edge and corner-sharing MnSb4 tetrahedra. All Mn–Sb bond lengths are 2.86 Å. Sb3- is bonded in a 9-coordinate geometry to four equivalent Ba2+ and five Mn2+ atoms. O2- is bonded to four equivalent Ba2+ and two equivalent Mn2+ atoms to form a mixture of edge, face, and corner-sharing OBa4Mn2 octahedra. The corner-sharing octahedral tilt angles are 0°.
36 MATERIALS SCIENCE↗
Materials Data on La9(SbO)5 by Materials Project
La9(SbO)5 crystallizes in the tetragonal P4/n space group. The structure is three-dimensional. there are three inequivalent La+2.78+ sites. In the first La+2.78+ site, La+2.78+ is bonded in a distorted single-bond geometry to five Sb3- and one O2- atom. There are four shorter (3.34 Å) and one longer (3.39 Å) La–Sb bond lengths. The La–O bond length is 2.41 Å. In the second La+2.78+ site, La+2.78+ is bonded in a distorted single-bond geometry to five Sb3- and one O2- atom. There are a spread of La–Sb bond distances ranging from 3.30–3.37 Å. The La–O bond length is 2.39 Å. In the third La+2.78+ site, La+2.78+ is bonded in a 4-coordinate geometry to two equivalent Sb3- and four O2- atoms. There are one shorter (3.47 Å) and one longer (3.55 Å) La–Sb bond lengths. There are a spread of La–O bond distances ranging from 2.32–2.63 Å. There are two inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded to five La+2.78+ atoms to form distorted SbLa5 square pyramids that share corners with four equivalent OLa4 tetrahedra and a cornercorner with one OLa5 trigonal bipyramid. In the second Sb3- site, Sb3- is bonded in a 7-coordinate geometry to seven La+2.78+ atoms. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five La+2.78+ atoms to form distorted OLa5 trigonal bipyramids that share a cornercorner with one SbLa5 square pyramid, corners with four equivalent OLa4 tetrahedra, and edges with four equivalent OLa4 tetrahedra. In the second O2- site, O2- is bonded to four La+2.78+ atoms to form OLa4 tetrahedra that share a cornercorner with one SbLa5 square pyramid, corners with four equivalent OLa4 tetrahedra, a cornercorner with one OLa5 trigonal bipyramid, an edgeedge with one OLa4 tetrahedra, and an edgeedge with one OLa5 trigonal bipyramid.
36 MATERIALS SCIENCE↗
Materials Data on Pr9(SbO)5 by Materials Project
Pr9(SbO)5 crystallizes in the tetragonal P4/n space group. The structure is three-dimensional. there are three inequivalent Pr sites. In the first Pr site, Pr is bonded in a 4-coordinate geometry to two equivalent Sb and four O atoms. There are one shorter (3.45 Å) and one longer (3.54 Å) Pr–Sb bond lengths. There are a spread of Pr–O bond distances ranging from 2.30–2.57 Å. In the second Pr site, Pr is bonded in a distorted single-bond geometry to five Sb and one O atom. There are one shorter (3.30 Å) and four longer (3.31 Å) Pr–Sb bond lengths. The Pr–O bond length is 2.46 Å. In the third Pr site, Pr is bonded in a distorted single-bond geometry to five Sb and one O atom. There are a spread of Pr–Sb bond distances ranging from 3.25–3.33 Å. The Pr–O bond length is 2.39 Å. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to five Pr atoms to form SbPr5 square pyramids that share corners with four equivalent OPr4 tetrahedra and a cornercorner with one OPr5 trigonal bipyramid. In the second Sb site, Sb is bonded in a 7-coordinate geometry to seven Pr atoms. There are two inequivalent O sites. In the first O site, O is bonded to five Pr atoms to form distorted OPr5 trigonal bipyramids that share a cornercorner with one SbPr5 square pyramid, corners with four equivalent OPr4 tetrahedra, and edges with four equivalent OPr4 tetrahedra. In the second O site, O is bonded to four Pr atoms to form OPr4 tetrahedra that share a cornercorner with one SbPr5 square pyramid, corners with four equivalent OPr4 tetrahedra, a cornercorner with one OPr5 trigonal bipyramid, an edgeedge with one OPr4 tetrahedra, and an edgeedge with one OPr5 trigonal bipyramid.
36 MATERIALS SCIENCE↗
Materials Data on Dy9(SbO)5 by Materials Project
Dy9(SbO)5 crystallizes in the tetragonal P4/n space group. The structure is three-dimensional. there are three inequivalent Dy sites. In the first Dy site, Dy is bonded in a distorted single-bond geometry to five Sb and one O atom. There are one shorter (3.14 Å) and four longer (3.16 Å) Dy–Sb bond lengths. The Dy–O bond length is 2.34 Å. In the second Dy site, Dy is bonded in a distorted single-bond geometry to five Sb and one O atom. There are a spread of Dy–Sb bond distances ranging from 3.09–3.18 Å. The Dy–O bond length is 2.28 Å. In the third Dy site, Dy is bonded in a 4-coordinate geometry to two equivalent Sb and four O atoms. There are one shorter (3.31 Å) and one longer (3.38 Å) Dy–Sb bond lengths. There are a spread of Dy–O bond distances ranging from 2.19–2.45 Å. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded in a 5-coordinate geometry to seven Dy atoms. In the second Sb site, Sb is bonded to five Dy atoms to form SbDy5 square pyramids that share corners with four equivalent ODy4 tetrahedra and a cornercorner with one ODy5 trigonal bipyramid. There are two inequivalent O sites. In the first O site, O is bonded to five Dy atoms to form distorted ODy5 trigonal bipyramids that share a cornercorner with one SbDy5 square pyramid, corners with four equivalent ODy4 tetrahedra, and edges with four equivalent ODy4 tetrahedra. In the second O site, O is bonded to four Dy atoms to form ODy4 tetrahedra that share a cornercorner with one SbDy5 square pyramid, corners with four equivalent ODy4 tetrahedra, a cornercorner with one ODy5 trigonal bipyramid, an edgeedge with one ODy4 tetrahedra, and an edgeedge with one ODy5 trigonal bipyramid.
36 MATERIALS SCIENCE↗
Materials Data on Tb9(SbO)5 by Materials Project
Tb9(SbO)5 crystallizes in the tetragonal P4/n space group. The structure is three-dimensional. there are three inequivalent Tb sites. In the first Tb site, Tb is bonded in a distorted single-bond geometry to five Sb and one O atom. There are a spread of Tb–Sb bond distances ranging from 3.11–3.19 Å. The Tb–O bond length is 2.29 Å. In the second Tb site, Tb is bonded in a distorted single-bond geometry to five Sb and one O atom. There are one shorter (3.16 Å) and four longer (3.18 Å) Tb–Sb bond lengths. The Tb–O bond length is 2.36 Å. In the third Tb site, Tb is bonded in a 4-coordinate geometry to two equivalent Sb and four O atoms. There are one shorter (3.32 Å) and one longer (3.40 Å) Tb–Sb bond lengths. There are a spread of Tb–O bond distances ranging from 2.21–2.46 Å. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded in a 5-coordinate geometry to seven Tb atoms. In the second Sb site, Sb is bonded to five Tb atoms to form SbTb5 square pyramids that share corners with four equivalent OTb4 tetrahedra and a cornercorner with one OTb5 trigonal bipyramid. There are two inequivalent O sites. In the first O site, O is bonded to four Tb atoms to form OTb4 tetrahedra that share a cornercorner with one SbTb5 square pyramid, corners with four equivalent OTb4 tetrahedra, a cornercorner with one OTb5 trigonal bipyramid, an edgeedge with one OTb4 tetrahedra, and an edgeedge with one OTb5 trigonal bipyramid. In the second O site, O is bonded to five Tb atoms to form distorted OTb5 trigonal bipyramids that share a cornercorner with one SbTb5 square pyramid, corners with four equivalent OTb4 tetrahedra, and edges with four equivalent OTb4 tetrahedra.
36 MATERIALS SCIENCE↗
Materials Data on Sm9(SbO)5 by Materials Project
Sm9(SbO)5 crystallizes in the tetragonal P4/n space group. The structure is three-dimensional. there are three inequivalent Sm+2.78+ sites. In the first Sm+2.78+ site, Sm+2.78+ is bonded in a 4-coordinate geometry to two equivalent Sb3- and four O2- atoms. There are one shorter (3.38 Å) and one longer (3.46 Å) Sm–Sb bond lengths. There are a spread of Sm–O bond distances ranging from 2.25–2.51 Å. In the second Sm+2.78+ site, Sm+2.78+ is bonded in a distorted single-bond geometry to five Sb3- and one O2- atom. There are a spread of Sm–Sb bond distances ranging from 3.18–3.25 Å. The Sm–O bond length is 2.33 Å. In the third Sm+2.78+ site, Sm+2.78+ is bonded in a distorted single-bond geometry to five Sb3- and one O2- atom. There are one shorter (3.22 Å) and four longer (3.23 Å) Sm–Sb bond lengths. The Sm–O bond length is 2.41 Å. There are two inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded in a 7-coordinate geometry to seven Sm+2.78+ atoms. In the second Sb3- site, Sb3- is bonded to five Sm+2.78+ atoms to form SbSm5 square pyramids that share corners with four equivalent OSm4 tetrahedra and a cornercorner with one OSm5 trigonal bipyramid. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five Sm+2.78+ atoms to form distorted OSm5 trigonal bipyramids that share a cornercorner with one SbSm5 square pyramid, corners with four equivalent OSm4 tetrahedra, and edges with four equivalent OSm4 tetrahedra. In the second O2- site, O2- is bonded to four Sm+2.78+ atoms to form OSm4 tetrahedra that share a cornercorner with one SbSm5 square pyramid, corners with four equivalent OSm4 tetrahedra, a cornercorner with one OSm5 trigonal bipyramid, an edgeedge with one OSm4 tetrahedra, and an edgeedge with one OSm5 trigonal bipyramid.
36 MATERIALS SCIENCE↗
Materials Data on Ce9(SbO)5 by Materials Project
Ce9(SbO)5 crystallizes in the tetragonal P4/n space group. The structure is three-dimensional. there are three inequivalent Ce sites. In the first Ce site, Ce is bonded in a distorted single-bond geometry to five Sb and one O atom. There are four shorter (3.26 Å) and one longer (3.33 Å) Ce–Sb bond lengths. The Ce–O bond length is 2.33 Å. In the second Ce site, Ce is bonded in a distorted single-bond geometry to five Sb and one O atom. There are a spread of Ce–Sb bond distances ranging from 3.22–3.29 Å. The Ce–O bond length is 2.31 Å. In the third Ce site, Ce is bonded in a 4-coordinate geometry to two equivalent Sb and four O atoms. There are one shorter (3.38 Å) and one longer (3.48 Å) Ce–Sb bond lengths. There are a spread of Ce–O bond distances ranging from 2.29–2.55 Å. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to five Ce atoms to form distorted SbCe5 square pyramids that share corners with four equivalent OCe4 tetrahedra and a cornercorner with one OCe5 trigonal bipyramid. In the second Sb site, Sb is bonded in a 7-coordinate geometry to seven Ce atoms. There are two inequivalent O sites. In the first O site, O is bonded to five Ce atoms to form distorted OCe5 trigonal bipyramids that share a cornercorner with one SbCe5 square pyramid, corners with four equivalent OCe4 tetrahedra, and edges with four equivalent OCe4 tetrahedra. In the second O site, O is bonded to four Ce atoms to form OCe4 tetrahedra that share a cornercorner with one SbCe5 square pyramid, corners with four equivalent OCe4 tetrahedra, a cornercorner with one OCe5 trigonal bipyramid, an edgeedge with one OCe4 tetrahedra, and an edgeedge with one OCe5 trigonal bipyramid.
36 MATERIALS SCIENCE↗
The interplay of microstructure and magnetism in La{sub 3}Ni{sub 2}SbO{sub 9}
La{sub 3}Ni{sub 2}SbO{sub 9} adopts a perovskite-related structure in which the six-coordinate cation sites are occupied alternately by Ni{sup 2+} and a disordered arrangement of Ni{sup 2+}/Sb{sup 5+}. A polycrystalline sample has been studied by neutron diffraction in applied magnetic fields of 0≤H/kOe≤50 at 5 K. In 0 kOe, weak magnetic Bragg scattering consistent with the adoption of a G-type ferrimagnetic structure is observed; the ordered component of the magnetic moment was found to be 0.89(7) µ{sub B} per Ni{sup 2+} cation. This increased to 1.60(3) µ{sub B} in a field of 50 kOe. Transmission electron microscopy revealed variations in the Ni:Sb ratio across crystallites of the sample. It is proposed that these composition variations disrupt the magnetic superexchange interactions within the compound, leading to domain formation and a reduced average moment. The application of a magnetic field aligns the magnetisation vectors across the crystal and the average moment measured by neutron diffraction increases accordingly. The role played by variations in the local chemical composition in determining the magnetic properties invites comparison with the behaviour of relaxor ferroelectrics. - Graphical abstract: Composition variations across a crystal of La3Ni2SbO9 result in anomalous magnetic behavior. - Highlights: • Ordered magnetic moment of Ni{sup 2+} increases in an applied magnetic field. • Composition variations detected by electron microscopy. • Increase in magnetic moment can be explained by presence of composition variations.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Structure and properties of the Sr 2 In 1-x Sn x SbO 6 double perovskite
A series of n -type oxide double perovskite semiconductors, Sr 2 In 1-x Sn x SbO 6 (0 ≤ x ≤ 0.3) has been synthesized; Sn 4+ partially substitutes for In 3+ . 121 Sb and 119 Sn Mössbauer spectroscopy are employed to investigate the B-site cation ordering because this issue cannot be resolved by conventional diffraction techniques alone. Rigid ordering between In 3+ /Sn 4+ and Sb 5+ sites is revealed by the spectroscopic method, and hence in combination with the structural parameters extracted from the XRD structural refinements, the crystallographic structure of this series of compounds is depicted. Furthermore, the temperature dependent magnetic susceptibilities, band gaps, and carrier type are characterized, and the calculated band structure is presented.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Pressure tuning of Kitaev spin liquid candidate Na 3 Co 2 SbO 6
The search for Kitaev’s quantum spin liquid in real materials has recently expanded with the prediction that honeycomb lattices of divalent, high-spin cobalt ions could host the dominant bond-dependent exchange interactions required to stabilize the elusive entangled quantum state. The layered honeycomb Na 3 Co 2 SbO 6 has been singled out as a leading candidate provided that the trigonal crystal field acting on Co 3d orbitals, which enhances non-Kitaev exchange interactions between $J$ eff = $\frac{1}{2}$ spin-orbital pseudospins, is reduced. Here we show that applied pressure leads to anisotropic compression of the layered structure, significantly reducing the trigonal distortion of CoO 6 octahedra. Ferromagnetic correlations between pseudospins are enhanced in the spin-polarized (3 Tesla) phase up to about 60 GPa. Higher pressures drive a high-spin to low-spin transition destroying the $J$ eff = $\frac{1}{2}$ moments required to map the spin Hamiltonian into Kitaev’s model. The spin transition strongly suppresses the low-temperature magnetic susceptibility and appears to stabilize a paramagnetic phase driven by frustration. The possible emergence of frustrated magnetism of localized $S$ = $\frac{1}{2}$ moments opens the door for exploration of novel magnetic quantum states in compressed honeycomb lattices of divalent cobaltates.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗