| AVS 66th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Wednesday Sessions |
| Session MI+2D-WeM |
| Session: | Emerging Multifunctional Magnetic Materials I and Magnetocaloric Materials |
| Presenter: | Zheng Gai, Oak Ridge National Laboratory |
| Authors: | Q. Zou, Oak Ridge National Laboratory M. Fu, Oak Ridge National Laboratory Z. Wu, Oak Ridge National Laboratory L. Li, Oak Ridge National Laboratory A.-P. Li, Oak Ridge National Laboratory D.S. Parker, Oak Ridge National Laboratory A. Safat, Oak Ridge National Laboratory Z. Gai, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
The electronic structure inhomogeneity in Ni, Co and Ni doped BaFe2As2 122 single crystals are compared using scanning tunneling microscopy/spectroscopy (STM/S) at atomic level within the pure superconducting (SC) dome, coexisting of SC and antiferromagnetic (AFM) phase, and non-SC phase regions. K-means clustering statistic method is utilized to categorize the various nanometer-size inhomogeneous electronic states described here as ‘in-gap’, ‘L-shape’ and ‘S-shape’ states immersed into the SC matrix for Ni-and Co-doped 122, and L-shape and S-shape states into metallic matrix for Cr-doped 122. Although the relative percentages of in-gap, L-shape and S-shape states various in three samples, the total volume fraction of the three electronic states is quite similar, coincident with the electron (Ni0.04 and Co0.08) and hole (Cr0.04) numbers doped into the 122 compound. By combining the volume fractions of the three states, local density of the states (LDOS), field dependent behavior and global properties in these three sets of samples, the in-gap state in SC crystals is confirmed as magnetic impurity state from Co or Ni dopants, the L-shape state is identified as the spin density wave (SDW) which competes with the SC phase, and the S-shape state is found to be another form of magnetic order which constructively cooperates with the SC phase rather than competing with it. The comparison of the vortex structures indicates that those inhomogeneous electronic states serve as pinning centers for stabilizing the hexagonal vortex lattice.