We investigate structural,mechanical,thermodynamic,and thermoelectric properties of vanadium-based XVO3(X=Na,K,Rb)materials using density functional theory(DFT)based calculations.The structural and thermodynamic stabi...We investigate structural,mechanical,thermodynamic,and thermoelectric properties of vanadium-based XVO3(X=Na,K,Rb)materials using density functional theory(DFT)based calculations.The structural and thermodynamic stabilities are probed by the tolerance factor(0.98,1.01,and 1.02)with the negative value of enthalpy of formation.Mechanical properties are analyzed in the form of Born stability criteria,ductile/brittle nature(Poisson and Pugh's ratios)and anisotropy factor.To explore the electronic transport properties,we study the electrical conductivity,thermal conductivity,Seebeck coefficient and power factor in terms of chemical potential and temperature.High values of Seebeck coefficient at room temperature may find the potential of the studied perovskites in thermo-electrics devices.展开更多
The effect of cold high pressure densification(CHPD)on anisotropy of the critical current density(Jc)in《in situ》single core binary and alloyed MgB2 tapes has been determined as a function of temperatures at 4.2 K,20...The effect of cold high pressure densification(CHPD)on anisotropy of the critical current density(Jc)in《in situ》single core binary and alloyed MgB2 tapes has been determined as a function of temperatures at 4.2 K,20 K and 25 K as well as at applied magnetic fields up to 19 T.The study includes binary and C4H6O5(malic acid)doped MgB2 tapes before and after CHPD.It is remarkable that the CHPD process not only improved the Jc values,in particular at the higher magnetic fields,but also decreased the anisotropy ratio,Г=JC^///JC^⊥In binary MgB2 tapes,the anisotropy factor F increases with higher aspect ratios,even after applying CHPD.In malic acid(C4H6O5)doped tapes,however,the application of CHPD leads only to small enhancements ofГ,even for higher aspect ratios.This is attributed to the higher carbon content in the MgB2 filaments,which in turn is a consequence of the reduced chemical reaction path in the densified filaments.At all applied field values,it was found that CHPD processed C4H6O5 doped tapes exhibit an almost isotropic behavior.This constitutes an advantage in view of industrial magnet applications using wires with square or slightly rectangular configuration.展开更多
文摘We investigate structural,mechanical,thermodynamic,and thermoelectric properties of vanadium-based XVO3(X=Na,K,Rb)materials using density functional theory(DFT)based calculations.The structural and thermodynamic stabilities are probed by the tolerance factor(0.98,1.01,and 1.02)with the negative value of enthalpy of formation.Mechanical properties are analyzed in the form of Born stability criteria,ductile/brittle nature(Poisson and Pugh's ratios)and anisotropy factor.To explore the electronic transport properties,we study the electrical conductivity,thermal conductivity,Seebeck coefficient and power factor in terms of chemical potential and temperature.High values of Seebeck coefficient at room temperature may find the potential of the studied perovskites in thermo-electrics devices.
基金This work was supported by the Australian Research Council(Grant No.LP160101784)A.K.thanks the Researchers Supporting Project(RSP-2019/127)King Saud University,Riyadh,Saudi Arabia for the support.This work was performed in part at the Queensland node of the Australian National Fabrication Facility,a company established under the National Collaborative Research Infrastructure Strategy to provide nano-and microfabrication facilities for Australia's researchers.M.M.acknowledges an internal funding project of the University of Osijek(ZUP-2018).
文摘The effect of cold high pressure densification(CHPD)on anisotropy of the critical current density(Jc)in《in situ》single core binary and alloyed MgB2 tapes has been determined as a function of temperatures at 4.2 K,20 K and 25 K as well as at applied magnetic fields up to 19 T.The study includes binary and C4H6O5(malic acid)doped MgB2 tapes before and after CHPD.It is remarkable that the CHPD process not only improved the Jc values,in particular at the higher magnetic fields,but also decreased the anisotropy ratio,Г=JC^///JC^⊥In binary MgB2 tapes,the anisotropy factor F increases with higher aspect ratios,even after applying CHPD.In malic acid(C4H6O5)doped tapes,however,the application of CHPD leads only to small enhancements ofГ,even for higher aspect ratios.This is attributed to the higher carbon content in the MgB2 filaments,which in turn is a consequence of the reduced chemical reaction path in the densified filaments.At all applied field values,it was found that CHPD processed C4H6O5 doped tapes exhibit an almost isotropic behavior.This constitutes an advantage in view of industrial magnet applications using wires with square or slightly rectangular configuration.
