  57Fe and 151Eu Moessbauer spectra were obtained versus temperature for
Eu0.57Ca0.43Fe2As2 compound with 3d and 4f magnetic order and
Eu0.73Ca0.27(Fe0.87Co0.13)2As2 re-entrant superconductor, where the finite
resistivity reappears while approaching the ground state. They were compared
with previously obtained spectra for parent compounds EuFe2As2 and CaFe2As2. It
was found that substitution beyond the Fe-As layers does not lead to the
rotation (canting) of the Eu2+ magnetic moments and does not generate Eu3+
states. On the other hand, re-entrant superconductor exhibits rotation
(canting) of the Eu2+ moments on the c-axis of the unit cell leading to the
transferred hyperfine magnetic field on iron nuclei. Divalent europium orders
magnetically within the bulk of the re-entrant superconducting phase. The
re-entrant superconductor remains in the inhomogeneous state close to the
ground state with about 27 % of the volume being free of 3d magnetism, while
the remainder exhibits weak spin density wave. Those two regions slightly
differ by the electric field gradient and electron density on iron nuclei.

Superconductivity;Strongly Correlated Electrons