Synthesis and Superconductivity of New BiS2 Based Superconductor PrO0.5F0.5BiS2

We report synthesis and superconductivity at 3.7 K in PrO_0.5F_0.5BiS₂. The newly discovered material belongs to the layered sulfide based REO_0.5F_0.5BiS₂ compounds having a ZrCuSiAs-type structure. The bulk polycrystalline compound is synthesized by the vacuum encapsulation technique at 780 ^°C in a single step. Detailed structural analysis has shown that the as synthesized PrO_0.5F_0.5BiS₂ is crystallized in a tetragonal P4/nmm space group with lattice parameters a=4.015(5) Å, c=13.362(4) Å. Bulk superconductivity is observed in PrO_0.5F_0.5BiS₂ below 4 K from magnetic and transport measurements. Electrical transport measurements showed superconducting transition temperature (T _c ) onset at 3.7 K and T _c (ρ=0) at 3.1 K. The hump at T _c related to the superconducting transition is not observed in the heat capacity measurement and rather a Schottky-type anomaly is observed at below ～6 K. The compound is slightly semiconducting in a normal state. Isothermal magnetization (MH) exhibited typical type II behavior with a lower critical field (H _c1) of around 8 Oe.     

Electrical and Magnetic Behaviour of PrFeAsO_{\mathbf{0.8}}F_{\mathbf{0.2}} Superconductor

The superconducting and ground state samples of PrFeAsO_0.8F_0.2 and PrFeAsO have been synthesised via the easy and versatile single step solid state reaction route. X-ray and Reitveld refine parameters of the synthesised samples are in good agreement to the earlier reported value of the structure. The ground state of the pristine compound (PrFeAsO) exhibited a metallic-like step in resistivity below 150 K followed by another step at 12 K. The former is associated with the spin density wave (SDW)-like ordering of Fe spins and later to the anomalous magnetic ordering for Pr moments. Both the resistivity anomalies are absent in case of the superconducting PrFeAsO_0.8F_0.2 sample. Detailed high field (up to 12 Tesla) electrical and magnetization measurements are carried out for the superconducting PrFeAsO_0.8F_0.2 sample. The PrFeAsO_0.8F_0.2 exhibited superconducting onset ( $T_{c}^{\mathrm{onset}}$ ) at around 47 K with T _c (ρ=0) at 38 K. Though the $T_{c}^{\mathrm{onset}}$ remains nearly invariant, the T _c (ρ=0) is decreased with applied field, and the same is around 23 K under an applied field of 12 Tesla. The upper critical field (H _c2) is estimated from the Ginzburg–Landau equation (GL) fitting, which is found to be ～182 Tesla. Critical current density (J _c ), being calculated from high field isothermal magnetization (MH) loops with the help of Beans critical state model, is found to be of the order of 10³ A/cm². Summarily, the superconductivity characterization of the single step synthesised PrFeAsO_0.8F_0.2 superconductor is presented.     

Superconductivity at 25 K under Hydrostatic Pressure for FeTe 0 . 5 Se 0 . 5 Superconductor

We report the impact of hydrostatic pressure on the superconductivity and normal-state resistivity of FeTe_0.5Se_0.5 superconductor. At the ambient pressure, the FeTe_0.5Se_0.5 compound shows the superconducting transition temperature \(T_{\mathrm {c}}^{\text {onset}} \) at above 13 K and \(T_{\mathrm {c}}^{\rho =0} \) at 11.5 K. We measure pressure-dependent resistivity from 250 to 5 K, which shows that the normal-state resistivity increases initially for the applied pressures of up to 0.55 GPa, and then the same is decreased monotonically with increasing pressure of up to 1.97 GPa. On the other hand, the superconducting transition temperatures ( \(T_{\mathrm {c}}^{\text {onset}} \) and \(T_{\mathrm {c}}^{\rho =0} )\) increase monotonically with increasing pressure. Namely the \(T_{\mathrm {c}}^{\text {onset}} \) increases from 13 to 25 K and \(T_{\mathrm {c}}^{\rho =0} \) from 11.5 to 20 K for the pressure range of 0–1.97 GPa. Our results suggest that superconductivity in this class of Fe-based compounds is very sensitive to pressure as the estimated pressure coefficient d T _c(onset)/dP is ～5.8 K/GPa. It may be suggested that the FeTe_0.5Se_0.5 superconductor is a strong electron-correlated system. The enhancement of T _c with applying pressure is mainly attributed to an increase of charge carriers at the Fermi surface.     

Cu, Pu and Fe High T c Superconductors: All the Same Mechanism

The more than 20 years old Cu high-T _c superconductors exhibit as undoped parent materials antiferromagnetism. Upon doping the long-range antiferromagnetism disappears and only short-range antiferromagnetic clusters remain which show a spin pseudo-gap. There are no good ideas why long-range antiferromagnetism disappears upon the appearance of superconductivity because antiferromagnetism and superconductivity are compatible. A breakthrough has come about with the discovery of a plutonium (Pu) containing alloy PuCoGa₅ with a T _c of 18.5 K. In principle not very exciting, but in the field of actinides T _c??s are not more than 3 K because of the high mass and corresponding low phonon energies. The compound is a high-T _c material in the field of actinides. But also this Pu-containing compound is a short-range antiferromagnet with a spin pseudo-gap. A pattern starts to develop! As well in the Cu as in the Pu compounds, some magnetic ions Cu²⁺ and Pu³⁺ are replaced upon doping with nonmagnetic Cu³⁺ or spontaneously with nonmagnetic Pu²⁺ ions, thus a mixed valence configuration appears with nonmagnetic states (spin holes) in antiferromagnetic clusters. The newly discovered Fe pnictide superconductors, however, have only one valence, Fe²⁺ above and below T _N, the Néel temperature of 150 K, as well above and below T _c, as judged by the isomer shift of the Mössbauer effect. However, doping with fluorine, replacing oxygen, not only introduces electrons, but changes locally the crystal field acting on the iron ions. Divalent iron 3d⁶ has a high-spin configuration $\mathrm{t}_{2}^{4}\mathrm{e}^{2}$ in a magnetic ??₅ configuration and a nonmagnetic low-spin configuration $\mathrm{t}_{2}^{6}$ in a ??₁ state. So with the same valence we can have a magnetic and a nonmagnetic configuration, triggered by variation of the local crystal field induced by doping, causing again spin holes. We show that these spin holes in antiferromagnetic clusters have an attractive interaction and combine to make nonmagnetic bipolarons, which can condense and lead to superconductivity.     

Decomposition of the Heusler alloy Cu2MnAl at 360°C

During thermomagnetic studies, the as-quenched Heusler alloy Cu_2.00 Mn_1.00 Al_1.01 exhibits two Curie temperatures \(\theta _{C_I } \) and \(\theta _{C_{II} } \) . After 98 h at 360° C, above the Curie point, X-ray diffraction patterns indicate two ferromagnetic phases: Cu₂MnAl (I) witha _I=5.8707 Å and \(\theta _{C_I } \) = 151 ± 10° C; Cu₂MnAl (II) witha _II=5.9656 Å and \(\theta _{C_{II} } \) = 332 ± 4° C, whereas the 850° C as-quenched alloy exhibitsa=5.9612 Å andθ _c=341±5° C. The results are discussed in terms of the early stages of the decomposition of the Heusler phase. A mechanism, involving mainly the atomic migration of manganese, is suggested in order to reach the equilibrium phases of the ternary Cu-Mn-Al diagram. The kinetics of the decomposition should be ruled by the nucleation and the growth of the Cu₃Mn₂Al intermetallic compound.     

Transport Properties of the Iron-based Superconductor SrFe2(As,P)2 in High Magnetic Fields

We have investigated the resistive upper critical field (μ ₀ H _c2) of the iron-based superconductor SrFe₂(As_1?x P _x )₂ (x=0.35, T _c～29 K) in pulsed high magnetic fields of up to 52 T. For H∥ab, $\mu_{0}H_{\mathrm{c}2}^{ab}(T)$ exhibits the Werthamer-Helfand-Hohenberg (WHH) like behavior. While, for H∥c, $\mu_{0}H_{\mathrm {c}2}^{c}(T)$ is almost linear against T and exhibits a slightly upward curvature near T _c. The anisotropy of μ ₀ H _c2 decreases from 2.5 near T _c to ～1.2 at T=0 K monotonically. Similar isotropic behavior of μ ₀ H _c2 at low temperatures has also been observed in the Fe_1+δ (Te,Se). We demonstrate the results of the two-band analysis for μ ₀ H _c2(T) on the present sample and discuss the anisotropy of μ ₀ H _c2 by comparing with those in some kinds of iron-based superconductors.     

Improved microwave dielectric properties of La(Mg0.5Sn0.5)O3 ceramic with Ba2+ substitution

The microwave dielectric properties of La(Mg_0.5?xBa_xSn_0.5)O₃ ceramics were examined with a view to their exploitation for wireless communications. The La(Mg_0.5?xBa_xSn_0.5)O₃ ceramics were prepared by the conventional solid-state method with various sintering temperatures. The La(Mg_0.5?xBa_xSn_0.5)O₃ ceramics contained La₂Sn₂O₇. An apparent density of 6.54 g/cm³, a dielectric constant ( $ \varepsilon_{r} $ ε r ) of 20.1, a quality factor (Q  $ \times $ ×  f) of 51,600 GHz, and a temperature coefficient of resonant frequency ( $ \tau_{f} $ τ f ) of ?82 ppm/°C were obtained for La(Mg_0.43Ba_0.07Sn_0.5)O₃ ceramics that were sintered at 1,550 °C for 4 h.     

Temperature Dependence of \sqrt{2} \times \sqrt{2} Phase in Superconducting K0.8Fe1.6Se2 Single Crystal

We report the structural phase transition properties of the newly discovered K_0.8Fe_1.6Se₂ superconductor (T _c =31.8 K) using synchrotron single-crystal X-ray diffraction. The basic structure of the sample at room temperature is found to be tetragonal ThCr₂Si₂-type, modulated by a vacancy ordering induced superlattice structure together with a coexisting minority phase having a $\sqrt{2} \times \sqrt{2}$ ordering. At 520 K, the reflections corresponding to the $\sqrt{2} \times \sqrt{2}$ phase merge with the parent tetragonal phase. The superlattice peaks corresponding to the vacancy ordering disappear at 580 K, indicating an order-disorder phase transition at this temperature.     

Theory of ion mobility in liquid3He

An ion interacting with quasiparticles in liquid³He is treated theoretically by summing most divergent terms in perturbation series of the self-energy of the ion and the vertex part. The ion Green's function is renormalized by a factorZ(T), and the vertex part byZ(T) ^?1, where \({\text{Z(T)}} = {\text{(T/T}}_F {\text{)}}^{{\text{2V}}_{{\text{0}}^{\rho ^{\text{2}} } }^{\text{2}} } \) , forT ₀?T?T _F. Here,T ₀=(m/M)T _F, withm the³He mass andM the ion mass, and \({\text{V}}_{0^\rho } \) is the strength of the interaction. The factor explains the weak temperature dependence of the mobility around the minimum atT ₀; we also discuss its effect on the behavior of the mobility in³He-B nearT _c.     

3He Vapor Pressure near Its Critical Point

Between 0.65 K and 3.2 K, the temperature dependence of the vapor pressure P of ³He is defined by the International Temperature Scale of 1990 (ITS-90). However, the ITS-90 vapor pressure equation was not designed to be consistent with the scaling law required for the second temperature derivative of the vapor pressure in the vicinity of the liquid-vapor critical point. In this paper, two scaling-type equations are used to describe the ³He vapor pressure in the region near the critical point. The first scaling equation contains two unknown coefficients which are obtained by taking as reference the temperature $\bar{T}$ at which the product (T _c ?T)P presents a maximum ( $\bar{T}=2.56736$  K). The second scaling equation contains three unknown coefficients which are obtained by using as references $\bar{T}$ and T _up=3.2 K, the upper value of the ITS-90 interval. In both equations we take for the critical temperature and pressure the values T _c =3.31554 K and P _c =114?632.7 Pa. The proposed equations, specially the second one, are satisfactorily compared with experimental data for P and dP/dT within the temperature range (T _c ?T)/T _c ≤0.065 and with semiempirical data for d ² P/dT ² within the temperature range 0.0001≤(T _c ?T)/T _c ≤0.03.     

Nb Substituted Cu0.5Tl0.5Ba2(Ca3Nb1)Cu5O_{14-\delta} and Cu0.5Tl0.5Ba2(Ca4Nb1)Cu6O_{16-\delta} Superconductors

The effects of higher electro-negativity Nb substitution on the Ca site in Cu_0.5Tl_0.5Ba₂ (Ca₃Nb₁)Cu₅O $_{14-\delta}$ and Cu_0.5Tl_0.5Ba₂(Ca₄Nb₁)Cu₆O $_{16-\delta}$ superconductors have been investigated. The Nb doping has been found to increase the oxygen contents in Cu_0.5Tl_0.5Ba₂O $_{16-\delta}$ charge reservoir layer of the final compound. The post-annealing in the N₂ atmosphere has been found to improve the superconducting properties; however, O₂ annealing produced the material with inferior superconducting properties. The quantity of diamagnetism is increased with post-annealing in the nitrogen atmosphere; as N₂ annealing helps in the formation of material with optimum carriers concentration in the CuO₂ planes, which is done by the change in the charge state of thallium from Tl³⁺ to Tl¹⁺. The Nb substitution has been found to develop the higher CuO₂ planner phases such as Cu_0.5Tl_0.5Ba₂Can _?2Nb₁Cun ₂ n+4?δ (n=5,6) with enhanced T _c's.     

Correlation Between Band Structure and Magneto- Transport Properties in HgTe/CdTe Two-Dimensional Far-Infrared Detector Superlattice

Theoretical calculations of the electronic properties of n-type HgTe/CdTe superlattices (SLs) have provided an agreement with the experimental data on the magneto-transport behaviour. We have measured the conductivity, Hall mobility, Seebeck and Shubnikov-de Haas effects and angular dependence of the magneto-resistance. Our sample, grown by MBE, had a period d=d ₁+d ₂ (124 layers) of $d_{1}=8.6~\mathrm{nm}~\mathrm{(HgTe)} /d_{2}=3.2~\mathrm{nm}~\mathrm{(CdTe)}$ . Calculations of the spectras of energy E(d ₂), E(k _z ) and E(k _p ), respectively, in the direction of growth and in plane of the superlattice; were performed in the envelope function formalism. The energy E(d ₂,Γ,4.2 K), shown that when d ₂ increase the gap E _g decrease to zero at the transition semiconductor to semimetal conductivity behaviour and become negative accusing a semimetallic conduction. At 4.2 K, the sample exhibits n type conductivity, confirmed by Hall and Seebeck effects, with a Hall mobility of $2.5 \times 10^{5}~\mathrm{cm}^{2}/ \mathrm{V\,s}$ . This allowed us to observe the Shubnikov-de Haas effect with n=3.20×10¹² cm^?2. Using the calculated effective mass ( $m^{*}_{E1}(E_{F}) = 0.05 m_{0}$ ) of the degenerated electrons gas, the Fermi energy (2D) was E _F =88 meV in agreement with 91 meV of thermoelectric power α. In intrinsic regime, α～T ^?3/2 and R _H T ^3/2 indicates a gap E _g =E ₁?HH ₁=101 meV in agreement with calculated E _g (Γ,300 K)=105 meV. The formalism used here predicts that the system is semiconductor for d ₁/d ₂=2.69 and d ₂<100 nm. Here, d ₂=3.2 nm and E _g (Γ,4.2 K)=48 meV so this sample is a two-dimensional modulated nano-semiconductor and far-infrared detector (12 μm<λ _c <28 μm).     

The Splitting of SDW State into Commensurable and Incommensurables Ones and the Peculiarities of the Behavior of Thermodynamic Quantities in a Magnetic Field Arbitrarily Oriented to Magnetization in Quasi Two-Dimensional Systems

The quasi-two-dimensional system in which magnetism is caused by spin density wave (SDW) with an anisotropic energy spectrum (with defined impurity concentration x) is examined. The wave vector $\vec{Q}$ is supposed to be different from 2k _F and the umklapp scattering (U-processes) is taken into account. The system is placed in a magnetic field arbitrarily oriented with respect to the vector $\vec{M}_{Q}$ . The basic equations for order parameters $M_{Q}^{z}, M_{Q}', M_{z}, M^{\sigma}$ are obtained and the system of these equations is transformed taking into account the U-processes. The particular cases $( \tilde{H} \Vert \vec{M}_{Q} )$ and $( \tilde{H} \bot \vec{M}_{Q} )$ and the case of small arbitrarily oriented magnetic fields $\vec{\tilde{H}}$ are examined in detail. The conditions of the system transition to commensurable and incommensurable SDW state are analyzed. The phase diagram (T,x) at H=0 is traced. The influence of the magnetic field $\vec{\tilde{H}}$ on the temperature of magnetic transition is researched and the aspect of the phase diagram in magnetic field in the cases H ^z H ^σ =0 is presented. The longitudinal magnetic susceptibility χ _∥ which demonstrates that at x<x _c the temperature behavior is similar to the case when the system has a gap, and at x>x _c to a gapless case. At x～x _c in the dependence X _∥(T) a local maximum appears. The influence of the energy spectrum anisotropy on the system’s properties is researched. Also the angular anisotropy of the quantity χ _∥ at different values of T and x is determined.     

Improved microwave dielectric properties of Nd(Mg0.5Sn0.5)O3 ceramics with Ni2+ substituting

This study elucidates the microwave dielectric properties and microstructures of Nd(Mg_0.5?xNi_xSn_0.5)O₃ ceramics with a view to their potential for microwave devices. The Nd(Mg_0.5?xNi_xSn_0.5)O₃ ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction patterns of the Nd(Mg_0.43Ni_0.07Sn_0.5)O₃ ceramics revealed no significant variation of phase with sintering temperatures. A dielectric constant ( $ \varepsilon_{r} $ ) of 19.3 and a quality factor (Q × f) of 93,400 GHz and a temperature coefficient of resonant frequency ( $ \tau_{f} $ ) of ?66 ppm/ °C were obtained for Nd(Mg_0.43Ni_0.07Sn_0.5)O₃ ceramics that were sintered at 1,550 °C for 4 h.     

Phase transitions and their co-existence in TlGaSe2–TlCrS2(Se2) systems

Investigation of dielectric properties of layered compound, TlGaSe₂, showed that it is a ferroelectric (T _c  = 105·5 K) with an intermediate incommensurate phase (T _i = 114·5 K). Our magnetic studies of layered compounds, TlCrS₂ and TlCrSe₂, for the first time revealed that the magnetic phase transition in these compounds are quasi two-dimensional ferromagnetic in nature and magnetic characteristics are T _C = 90 K, T $_{C}^{p}$ = 115 K, μ _eff = 3·26 μ _B and T _C = 105 K, T $_{C}^{p}$ = 120 K, μ _eff = 3·05 μ _B , respectively. Using the method of DTA, areas of homogeneous and heterogeneous coexistence of ferroelectric and ferromagnetic phase transitions in the systems, TlGaSe₂–TlCrS₂ and TlGaSe ₂–TlCrSe₂, were identified. The low-dimensional solid solutions and eutectic alloys in these systems can be used as basic materials for plenty of functional recorders.     

Multiple Andreev Reflections Spectroscopy of Two-Gap 1111- and 11 Fe-Based Superconductors

Using the “break-junction” technique, we prepared and studied superconductor–constriction–superconductor (ScS) nanocontacts in polycrystalline samples of Fe-based superconductors CeO_0.88F_0.12FeAs (Ce-1111; $T_{C}^{\mathrm{bulk}} = 41 \pm1~\mathrm{K}$ ), LaO_0.9F_0.1FeAs (La-1111; $T_{C}^{\mathrm{bulk}} = 28 \pm1~\mathrm {K}$ ), and FeSe ( $T_{C}^{\mathrm{bulk}} = 12 \pm1~\mathrm{K}$ ). We detected two subharmonic gap structures related with multiple Andreev reflections, indicating the presence of two superconducting gaps with the BCS-ratios 2Δ _L /k _B T _C =4.2÷5.9 and 2Δ _S /k _B T _C ～1?3.52, respectively. Temperature dependences of the two gaps Δ _L,S (T) in FeSe indicate a k-space proximity effect between two superconducting condensates. For the studied iron-based superconductors, we found a linear relation between the gap Δ _L and magnetic resonance energy, E _res≈2Δ _L .     

Superconductivity in Ca<Subscript>0.5</Subscript>La<Subscript>0.5</Subscript>FBiSe<Subscript>2</Subscript>

Through the measurement of resistivity, magnetic susceptibility, and Hall effect, we discovered a novel BiSe₂-based superconductor Ca_0.5La_0.5FBiSe₂ with T _c of 3.9 K. A strong diamagnetic signal below T _c in susceptibility χ(T) is observed indicating the bulk superconductivity. The negative Hall coefficient throughout the whole temperature regime implies the dominant electron-type carriers in the sample. Different to most of BiS₂-based compounds where superconductivity develops from a semiconducting-like normal state, its resistivity in the present compound exhibits a metallic behavior down to T _c . Together with the enhanced T _c , the metallic character of the normal state implies that the electronic structure of Ca_0.5La_0.5FBiSe₂ may be different to those in the other BiS₂-based compounds.     

Enhancement of piezoelectric properties and temperature stability by forming an MPB in KNN-based lead-free ceramics

0.92(Na_0.51K_0.49?x Li _x )NbO₃–0.02Bi_0.5K_0.5TiO₃–0.06BaZrO₃ (x = 0, 0.01, 0.02, 0.03, 0.04, and 0.05) lead-free piezoelectric ceramics were prepared by solid state reaction route. The effect of Li doping amount on the structure and electrical properties of the ceramics were investigated. All ceramics had pure perovskite structure, while the crystallographic symmetry changed from rhombohedral to tetragonal with the increase of Li doping amount. A PZT-like morphotropic phase boundary (MPB) with the coexistence of rhombohedral and tetragonal phases was identified in the composition of x = 0.03. As expected, the ceramics of the MPB composition showed optimal properties: piezoelectric coefficient d ₃₃ = 227 pC/N, planar electromechanical coupling coefficient k _p = 39.3 %, dielectric permittivity $ \varepsilon_{33}^{T} /\varepsilon_{0} $  = 1,640, dielectric loss tanδ = 2.0 %, remnant polarization P _r = 13.3 μC/cm², coercive field E _c = 1.53 kV/mm, and Curie temperature T _c = 253 °C. Together with good temperature stability to 200 °C, this KNN-based lead-free ceramics should be very promising for practical applications.     

Influence of Grain Size on the Superconductivity of?La1.85Sr0.15CuO4

We study the influence of varying grain size on superconductivity of bulk La_1.85Sr_0.15CuO₄ superconductor. The samples are synthesized by a sol-gel method. The grain size is varied by sintering the samples at various temperatures between 700?°C to 1050?°C. The samples are characterized by X-Ray Diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), resistivity and magnetization measurements. The electrical resistivity measurements revealed considerable lowering of the superconducting transition temperature ( $T_{\mathrm{c}}^{R=0}$ ) and broadening of the transition width (??T _c) with decreasing grain size though the onset of transition temperature ( $T_{\mathrm{c}}^{\mathrm{onset}}$ ) changes only marginally. The magnetic measurements carried out are consistent with each other and scale well with the grain size. Critical current density has been calculated from the magnetization hysteresis, assuming that supercurrents flow throughout the sample as a whole and within the individual grains as well. The observed results have been discussed on the basis of inter- and intra-granular boundary characteristics of high-temperature superconductors (HTSc). It is found that lowering of grain size deteriorates the superconducting properties in general.     

Three-Dimensional Network Polymeric Structure of (2-Amino-5 Ammoniopyridinium)[CuCl4]: Crystal Supramolecularity and Magnetic Properties

A single crystal structure determination of the complex (C₅H₉N₃)CuCl₄ [henceforth I] has been carried out. It crystallizes in the orthorhombic space group Cmca, with the cell parameters a=6.7053(5) Å, b=22.4171(19) Å, c=13.4173(9) Å, V=2016.8(3) Å³, and Z=8. In the complex, the anion is comprised of infinite zigzag chains of monochloro-bridged $\mathrm{CuCl}_{4}^{2-}$ units ?–CuCl₃–μ–Cl–CuCl₃–μ–Cl–CuCl₃–? surrounded by the pyridinium-ammonium cations. The Cu ions are five-coordinate to chloride ions in a distorted square-pyramidal geometry with the zigzag chains formed by corner-sharing polyhedra. The Cu ion is located 0.151 Å above the basal plane. In the crystal, there are four intermolecular hydrogen bonding interactions, linking the CuCl chains to the cations to form a 2D-network. The resulting 2D-networks are further linked by aryl?aryl (π?π) interactions within the cationic chains leading to a 3D-network. Variable temperature magnetic susceptibility data were fit to a one-dimensional S=1/2 antiferromagnetic chain model yielding C=0.44(1) emu-K/mol-Oe and J=?37(1) K.