Field-induced nematic-like magnetic transition in an iron pnictide superconductor, Ca(PtAs)((FePt)As)
arXiv:1310.3728 · doi:10.1103/PhysRevB.89.205136
Abstract
We report a high magnetic field study up to 55 T of the nearly optimally doped iron-pnictide superconductor Ca(PtAs) ((FePt)As) (x=0.078(6)) with a Tc 10 K using magnetic torque, tunnel diode oscillator technique and transport measurements. We determine the superconducting phase diagram, revealing an anisotropy of the irreversibility field up to a factor of 10 near Tc and signatures of multiband superconductivity. Unexpectedly, we find a spin-flop like anomaly in magnetic torque at 22 T, when the magnetic field is applied perpendicular to the ab planes, which becomes significantly more pronounced as the temperature is lowered to 0.33 K. As our superconducting sample lies well outside the antiferromagnetic region of the phase diagram, the observed field-induced transition in torque indicates a spin-flop transition not of long-range ordered moments, but of nematic-like antiferromagnetic fluctuations.
Latex, 4 figures
References in corpus (20)
- Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
- Nearly Isotropic superconductivity in (Ba,K)Fe2As2
- Nematic and meta-nematic transitions in the iron pnictides
- Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
- Upper critical fields and thermally-activated transport of Nd(O_0.7F_0.3)FeAs single crystal
- Lattice and magnetic instabilities in CaFe2As2: A single crystal neutron diffraction study
- Magnetism in Fe-based superconductors
- Fermi surface of superconducting LaFePO determined by quantum oscillations
- Crystal structure and phase transitions across the metal-superconductor boundary in the SmFeAsO1-xFx (0 < x < 0.20) family
- Pseudogap formation above the superconducting dome in iron-pnictides
- Spin excitation anisotropy as a probe of orbital ordering in the paramagnetic tetragonal phase of superconducting BaFe1.904Ni0.096As2
- Why of (CaFeAs)PtAs is twice as high as (CaFePtAs)PtAs
- Transport Properties and Electronic Phase Diagram of Single-Crystalline Ca(PtAs) ((FePt)As)
- Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFeNiAs
- Temperature-concentration phase diagram of (Ca1-xLax)10(Pt3As8)(Fe2As2)5 superconductors
- Quantum Oscillation Studies of the Fermi Surface of LaFePO
- Large magnetic penetration depth and thermal fluctuations in a Ca(PtAs)[(FePt)As] (x=0.097) single crystal
- Structural and magnetic phase transitions in triclinic Ca10(FeAs)10(Pt3As8)
- Antiferromagnetic order in Ca(PtAs)(FeAs) observed by As NMR
- Iron spin-reorientation transition in NdFeAsO