  We report on structural, magnetic and transport properties of a new set of
the high-pressuresynthesized compounds Mn$_{1-x}$Rh$x$Ge ($0 \leq x \leq 1$)
with the chiral magnetic ordering. The magnetic and transport properties depend
substantially on the concentration of rhodium (x) and the pressure. The
saturation magnetic moment corresponds to a known high-spin value for pristine
MnGe (x = 0) and decreases almost linearly with increasing concentration $x$.
In addition, XMCD spectra taken at 10 K and 2 T indicate magnetic polarization
of the Rh 4d electron states and Ge $4p$ states, which decreases with $x$, too.
In rhodium rich compounds ($x \geq 0.5$) the temperature of the magnetic
ordering increases significantly with pressure, whereas in manganese rich
compounds ($x < 0.5$) the temperature decreases. Three different tendencies are
also found for several structural and transport properties. In the intermediate
range ($0.3 \leq x \leq 0.7$) samples are semiconducting in the paramagnetic
phase, but become metallic in the magnetically ordered state. We carried out ab
initio density-functional calculations of Mn$_{1-x}$Rh$_x$Ge at various
concentrations $x$ and traced the evolution of electronic and magnetic
properties. The calculation results are in good agreement with the measured
magnetic moments and qualitatively explain the observed trends in transport
properties.
