  We report on the structural, electric and magnetic properties of
$(\mathrm{Ni}_x\mathrm{Co}_{1-x})\mathrm{B}$ ferromagnetic nanotubes,
displaying azimuthal magnetization. The tubes are fabricated using electroless
plating in polycarbonate porous templates, with lengths several tens of
micrometers, diameters from 100nm to 500nm and wall thicknesses from 10nm to
80nm. The resistivity is $\sim 1.5\times10^{-6}\mathrm{\Omega/m}$, and the
anisotropic magnetoresistance~(AMR) of 0.2-0.3%, one order of magnitude
larger~(resp. smaller) than in the bulk material, which we attribute to the
resistance at grain boundaries. We determined the azimuthal anisotropy field
from M(H) AMR loops of single tubes contacted electrically. Its magnitude is
around 10mT, and tends to increase with the tube wall thickness, as well as the
Co content. However, surprisingly it does not dependent much on the diameter
nor on the curvature.
