Presure-Induced Superconducting State of Antiferromagnetic CaFe${}_2$As${}_2$

Abstract

The antiferromagnet CaFe${}_2$As${}_2$ does not become superconducting when subject to ideal hydrostatic pressure conditions, where crystallographic and magnetic states also are well defined. By measuring electrical resistivity and magnetic susceptibility under quasi-hydrostatic pressure, however, we find that a substantial volume fraction of the sample is superconducting in a narrow pressure range where collapsed tetragonal and orthorhombic structures coexist. At higher pressures, the collapsed tetragonal structure is stabilized, with the boundary between this structure and the phase of coexisting structures strongly dependent on pressure history. Fluctuations in magnetic degrees of freedom in the phase of coexisting structures appear to be important for superconductivity.

revised (6 pages, 5 figures) - includes additional experimental results

References in corpus (20)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• Origin of the ~150 K Anomaly in LaOFeAs; Competing Antiferromagnetic Superexchange Interactions, Frustration, and Structural Phase Transition
• Superconductivity up to 29 K in SrFe2As2 and BaFe2As2 at high pressures
• Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Lattice and magnetic instabilities in CaFe2As2: A single crystal neutron diffraction study
• The Unprecedented Giant Coupling of Fe-spin State and the As-As Hybridization in Iron-Pnictide
• Magnetic and structural transitions in layered FeAs systems: AFe2As2 versus RFeAsO compounds
• Structural transition and anisotropic properties of single crystalline SrFe2As2
• Lattice collapse and quenching of magnetism in CaFe2As2 under pressure: A single crystal neutron and x-ray diffraction investigation
• Synthesis and Properties of CaFe${}_2$As${}_2$ Single Crystals
• Pressure-induced superconductivity in single crystal CaFe2As2
• Anisotropy, Itineracy, and Magnetic Frustration in High-Tc Iron Pnictides
• Muon spin relaxation studies of magnetic order and superfluid density in antiferromagnetic NdOFeAs, BaFe2As2 and superconducting (Ba,K)Fe2As2
• Pressure-induced superconductivity in Iron pnictide compound SrFe2As2
• First order magnetic transition in single crystal CaFe${}_2$As${}_2$ detected by ${}^{75}$As NMR
• Effect of pressure on the magnetostructural transition in SrFe2As2
• NMR investigation of superconductivity and antiferromagnetism in CaFe${}_2$As${}_2$ under pressure
• Competition/Coexisitence of Magnetism and Superconductivity in Iron Pnictides Probed by Muon Spin Rotation

Cited by in corpus (1)

• Microscopic origin of pressure-induced phase transitions in iron-pnictide $AF{e}_{2}A{s}_2$ superconductors: an {ab initio} molecular-dynamics study