  Results of muon spin relaxation ($\mu$SR) and neutron powder diffraction
measurements on a reentrant superconductor Eu(Fe$_{0.86}$Ir$_{0.14}$)$_2$As$_2$
are presented. Eu(Fe$_{0.86}$Ir$_{0.14}$)$_2$As$_2$ exhibits superconductivity
at $T_{\rm c\,on} \approx 22.5$~K competing with long range ordered Eu$^{+2}$
moments below $\approx 18$ K. A reentrant behavior (manifested by nonzero
resistivity in the temperature range 10--17.5 K) results from an exquisite
competition between the superconductivity and magnetic order. The zero field
$\mu$SR data confirm the long range magnetic ordering below $T_{\rm Eu} =
18.7(2)$ K. The transition temperature is found to increase with increasing
magnetic field in longitudinal field $\mu$SR which along with the neutron
diffraction results, suggests the transition to be ferromagnetic. The neutron
diffraction data reveal a clear presence of magnetic Bragg peaks below $T_{\rm
Eu}$ which could be indexed with propagation vector k = (0, 0, 0), confirming a
long range magnetic ordering in agreement with $\mu$SR data. Our analysis of
the magnetic structure reveals an ordered magnetic moment of $6.29(5)\,\mu_{\rm
B}$ (at 1.8 K) on the Eu atoms and they form a ferromagnetic structure with
moments aligned along the $c$-axis. No change in the magnetic structure is
observed in the reentrant or superconducting phases and the magnetic structure
remains same for 1.8 K $\leq T \leq T_{\rm Eu}$. No clear evidence of
structural transition or Fe moment ordering was found.

Superconductivity;Strongly Correlated Electrons