Angular dependent transport properties of MgB2 films with columnar grains

We studied the angular dependence of the transport properties of MgB2 films with columnar grains grown by hybrid physical chemical vapor deposition method, one sample with unreacted boron in the volume and the other sample with no traceable impurity phase. The angular dependence of resistivity and critical current density in applied magnetic fields for both samples showed a flux pinning effect by the grain boundaries between columnar grains. The temperature dependence of the upper critical fields was analyzed by using the dirty-limit two-gap model. We found that the unreacted boron in the body of the film had negative effect on flux pinning and intraband electron diffusivities