  Here we report the fabrication and characterization of fully superconducting
quantum interference proximity transistors (SQUIPTs) based on the
implementation of vanadium (V) in the superconducting loop. At low temperature,
the devices show high flux-to-voltage (up to 0.52$\ \textrm{mV}/\Phi_0$) and
flux-to-current (above 12$\ \textrm{nA}/\Phi_0$) transfer functions, with the
best estimated flux sensitivity $\sim$2.6$\ \mu\Phi_0/\sqrt{\textrm{Hz}}$
reached under fixed voltage bias, where $\Phi_0$ is the flux quantum. The
interferometers operate up to $T_\textrm{bath}\simeq$ 2 $ \textrm{K}$, with an
improvement of 70$\%$ of the maximal operating temperature with respect to
early SQUIPTs design. The main features of the V-based SQUIPT are described
within a simplified theoretical model. Our results open the way to the
realization of SQUIPTs that take advantage of the use of higher-gap
superconductors for ultra-sensitive nanoscale applications that operate at
temperatures well above 1 K.
