  We observe a novel type of shear banding in the rheology of thixotropic
yield-stress fluids that is due to the coupling of both non-locality and
thixotropy. The latter is known to lead to shear banding even in homogeneous
stress fields, but the bands observed in the presence of non-local effects
appear different as the shear rate varies continuously over the shear band.
Here, we introduce a simple non-local model for the shear banding (NL-SB), and
we implement it for the analysis of micron-scale rheo-MRI velocimetry
measurements of a milk microgel suspension in a cone-and-plate geometry. The
proposed NL-SB model accurately quantifies the cooperativity length and yields
values in the order of the aggregate size in the microgel.
