We examined the magnetic properties of YbBe13, which exhibits an
antiferromagnetic order below TN = 1.2 K. Unlike other MBe13 compounds (M =
rare earth/actinide elements), based on elastic neutron scattering, we observed
an incommensurate magnetic propagation vector {\tau} = (0,0,{\tau}z), where
{\tau}z = 0.5385 is in the reciprocal lattice unit. Additionally, we
constructed a precise magnetic phase diagram for YbBe13. We observed
non-trivial magnetic anomalies in YbBe13, which cannot be understood based on a
simple helical order. Our results for YbBe13 provide an opportunity to
reconsider the electron state of UBe13 and present an important step toward a
comprehensive understanding of magnetic correlations in MBe13 series.Comment: 5 pages, 5 figure