  The magnetic and quadrupolar ordered states of polycrystalline YbRu2Ge2 have
been investigated using zero-field muon spin relaxation ({\mu}SR) and neutron
diffraction measurements. Specific heat measurements show three successive
phase transitions, with decreasing temperature from a paramagnetic to a
quadrupolar state at T0 ~ 10 K, from the quadrupolar to a magnetic state at T1
~ 6.5 K and a possible change in the magnetic ground state at T2 ~ 5.5 K. Clear
evidence for the magnetic transition below 7 K (spectrum at 8 K reveals
paramagnetic state) and a likely change in the magnetic structure near 5.8 K is
observed in the zero-field {\mu}SR measurements. The {\mu}SR data, however, do
not reveal any signature of magnetic order in the temperature range 8 - 45 K.
This result is further supported by neutron diffraction measurements, where
clear magnetic Bragg peaks have been observed below 8 K, but not above it.
Below 8 K, the magnetic Bragg peaks can be characterized by an incommensurate
antiferromagnetic ordering with the propagation vector q = [0.352, 0, 0] and
the magnetic moment 2.9(3) {\mu}B of Yb along the b-axis. These results are
discussed in terms of quadrupolar ordered and magnetically ordered states.
