A polarized neutron diffraction study of the field-induced magnetization in the normal and superconducting states of Ba(Fe1-xCox)2As2 (x=0.65)

Abstract

We use polarised neutron diffraction to study the induced magnetization density of near optimally doped Ba(Fe0.935Co0.065)2As2 (T_C=24 K) as a function of magnetic field (1<H<9 T) and temperature (2<T<300 K). The T-dependence of the induced moment in the superconducting state is consistent with the Yosida function, characteristic of spin-singlet pairing. The induced moment is proportional to applied field for H < 9 T ~ Hc2/6. In addition to the Yosida spin-susceptibility, our results reveal a large zero-field contribution M (H=>0,T=>0)/H ~ 2/3 χ_{normal} which does not scale with the field or number of vortices and is most likely due to the van Vleck susceptibility. Magnetic structure factors derived from the polarization dependence of 15 Bragg reflections were used to make a maximum entropy reconstruction of the induced magnetization distribution in real space. The magnetization is confined to the Fe atoms and the measured density distribution is in good agreement with LAPW band structure calculations which suggest that the relevant bands near the Fermi energy are of the d_{xz/yz} and d_{xy} type.

References in corpus (19)

• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Determination of the phase diagram of the electron doped superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Electronic Structure and Doping in BaFe${}_2$As${}_2$ and LiFeAs: Density Functional Calculations
• ${}^{75}$As NMR studies of superconducting LaO${}_{0.9}$F${}_{0.1}$FeAs
• Scanning Tunneling Spectroscopy and Vortex Imaging in the Iron-Pnictide Superconductor BaFe${}_{1.8}$Co${}_{0.2}$As${}_2$
• Evidence for nodal superconductivity in LaFePO
• A neutron scattering study of the interplay between structure and magnetism in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Nodes in the gap structure of the iron-arsenide superconductor Ba(Fe_{1-x}Co_x)_2As_2 from c-axis heat transport measurements
• ^{31}P and ^{75}As NMR evidence for a residual density of states at zero energy in superconducting BaFe_2(As_{0.67}P_{0.33})_2
• On the multi-orbital band structure and itinerant magnetism of iron-based superconductors
• 59-Co and 75-As NMR Investigation of Electron-Doped High Tc Superconductor BaFe(1.8)Co(0.2)As(2) (Tc = 22K)
• Dispersive Spin Fluctuations in the near optimally-doped superconductor Ba(Fe1-xCox)2As2 ($x$=0.065)
• Doping evolution of the absolute value of the London penetration depth and superfluid density in single crystals of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Local measurement of the superfluid density in the pnictide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ across the superconducting dome
• Orbital character variation of the Fermi surface and doping dependent changes of the dimensionality in BaFe2-xCoxAs2 from angle-resolved photoemission spectroscopy
• Effect of annealing on the specific heat of Ba(Fe1-xCox)2As2
• The magnetic form factor of iron in SrFe2As2
• ${}^{75}$As NMR of Ba(Fe${}_{0.93}$Co${}_{0.07}$)${}_2$As${}_2$ in High Magnetic Field
• Magnetisation distribution in the tetragonal phase of BaFe2As2

Cited by in corpus (4)

• Antiferromagnetic order and spin dynamics in iron-based superconductors
• Superconductivity, Antiferromagnetism, and Neutron Scattering
• Reduction of the spin susceptibility in the superconducting state of Sr2RuO4 observed by polarized neutron scattering
• Magnetization distribution and orbital moment in the non-Superconducting Chalcogenide Compound K0.8Fe1.6Se2