  Compensated ferrimagnets are promising materials for fast spintronic
applications based on domain wall motion as they combine the favourable
properties of ferromagnets and antiferromagnets. They inherit from
antiferromagnets immunity to external fields, fast spin dynamics and rapid
domain wall motion. From ferromagnets they inherit straightforward ways to read
out the magnetic state, especially in compensated half metals, where electrons
flow in only one spin channel. Here, we investigate domain structure in
compensated half-metallic Mn2Ru0.5Ga films and assess their potential in domain
wall motion-based spin-electronic devices. Our focus is on understanding and
reducing domain wall pinning in unpatterned epitaxial thin films. Two modes of
magnetic reversal, driven by nucleation or domain wall motion, are identified
for different thin film deposition temperatures $(T_{dep})$. The magnetic
aftereffect is analysed to extract activation volumes $(V^*)$, activation
energies $(E_A)$, and their variation $({\Delta}E_A)$. The latter is decisive
for the magnetic reversal regime, where domain wall motion dominated reversal
(weak pinning) is found for ${\Delta}E_A<0.2$ eV and nucleation dominated
reversal (strong pinning) for ${\Delta}E_A>0.5$ eV. A minimum ${\Delta}E_A=28$
meV is found for $T_{dep}=290{\deg}$C. Prominent pinning sites are visualized
by analysing virgin domain patterns after thermal demagnetization. In the
sample investigated they have spacings of order 300 nm, which gives an upper
limit of the track-width of spin-torque domain-wall motion-based devices.
