  A scale for magnetic field resilience of a superconductor is set by the
paramagnetic limit. Comparing the condensation energy of the
Bardeen-Cooper-Schrieffer (BCS) singlet ground state with the paramagnetically
polarised state suggests that for an applied field ${\mu_0}H > 1.8~T_c$ (in
SI), singlet pairing is not energetically favourable. Materials exceeding or
approaching this limit are interesting from fundamental and technological
perspectives. This may be a potential indicator of triplet superconductivity,
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing and other mechanisms involving
topological aspects of surface states, and also allow Cooper pair injection at
high magnetic fields. We have analysed the microscopic composition of such a
material arising from an unexpected source. A microjet of an organo-metallic
gas, $\rm {W[(CO)_6]}$ can be decomposed by gallium ion-beam, leaving behind a
track of complex residue of gallium, tungsten and carbon with remarkable
superconducting properties, like an upper critical field, $H_{c2} > 10~{\rm T}
$, above its paramagnetic limit. We carried out Atomic probe tomography to
establish the formation of nano-crystalline tungsten carbide (WC) in the tracks
and the absence of free tungsten. Supporting calculations show for Ga
distributed on the surface of WC, its s,p-orbitals enhance the density of
states near the Fermi energy. The observed variation of $H_{c2}(T)$ does not
show features typical of enhancement of critical field due to granularity. Our
observations may be significant in the context of some recent theoretical
calculation of the band structure of WC and experimental observation of
superconductivity in WC-metal interface.

Superconductivity;Mesoscale and Nanoscale Physics;Materials Science;Strongly Correlated Electrons