  We report on the interplay between creep and residual stresses in a carbopol
microgel. When a constant shear stress $\sigma$ is applied below the yield
stress $\sigma_\text{y}$, the strain is shown to increase as a power law of
time, $\gamma(t)=\gamma_0 + (t/\tau)^\alpha$, with an exponent $\alpha=0.39\pm
0.04$ that is strongly reminiscent of Andrade creep in hard solids. For applied
shear stresses lower than some typical value $\sigma_\text{c}\simeq 0.2
\sigma_\text{y}$, the microgel experiences a more complex, anomalous creep
behaviour, characterized by an initial decrease of the strain, that we
attribute to the existence of residual stresses of the order of
$\sigma_\text{c}$ that persist after a rest time under a zero shear rate
following preshear. The influence of gel concentration on creep and residual
stresses are investigated as well as possible aging effects. We discuss our
results in light of previous works on colloidal glasses and other soft glassy
systems.
