  The scaling behavior over four decades of the ratio of temperature T to
magnetic field B observed in the magnetization in beta-YbAlB4 is theoretically
examined. By developing a theoretical framework that exhibits the quantum
critical phenomena of Yb-valence fluctuations under a magnetic field, we show
that the T/B-scaling behavior can appear near the quantum critical point of the
valence transition. The emergence of the T/B scaling indicates the presence of
the small characteristic energy scale of critical Yb-valence fluctuations. It
is argued that the quantum valence criticality offers a unified explanation for
the unconventional quantum criticality as well as the T/B scaling in
beta-YbAlB4.
