Park, J. T. Inosov, D. S. Niedermayer, Ch. Sun, G. L. Haug, D. Christensen, N. B. Dinnebier, R. Boris, A. V. Drew, Alan J. Schulz, Leander Shapoval, T. Wolff, U. Neu, V. Yang, Xiaoping Lin, C. T. Keimer, B. Hinkov, V. 2009-04-20 Here we present a combined study of the slightly underdoped novel pnictide superconductor Ba_1-<i>x</i>K_<i>x</i>Fe₂As₂ by means of x-ray powder diffraction, neutron scattering, muon-spin rotation (<i>µ</i>SR), and magnetic force microscopy (MFM). Static antiferromagnetic order sets in below <i>T</i>_<i>m</i>≈70 K as inferred from the neutron scattering and zero-field-<i>µ</i>SR data. Transverse-field <i>µ</i>SR below <i>T</i>_<i>c</i> shows a coexistence of magnetically ordered and nonmagnetic states, which is also confirmed by MFM imaging. We explain such coexistence by electronic phase separation into antiferromagnetic and superconducting- or normal-state regions on a lateral scale of several tens of nanometers. Our findings indicate that such mesoscopic phase separation can be considered an intrinsic property of some iron pnictide superconductors. application/pdf https://folia.unifr.ch/global/documents/301192 https://folia.unifr.ch/documents/301192/files/drew_eps.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevLett.102.117006 info:eu-repo/semantics/openAccess License undefined Physical Review Letters. - 2009, vol. 102, no. 111, p. 117006 info:eu-repo/classification/udc/53 Electronic phase separation in the slightly underdoped iron pnictide superconductor Ba_1-<i>x</i><b>K</b>_<i>x</i>Fe₂As₂ http://purl.org/coar/resource_type/c_6501