  Magnetoelectric mutual control in multiferroics, which is the electric
control of magnetization, or reciprocally the magnetic control of polarization
has attracted much attention because of its possible applications to spintronic
devices, multi-bit memories, and so on. While the required working temperature
for the practical application is much higher than room temperature, which
ensures stable functionality at room temperature, the reported working
temperatures were at most around room temperature. Here, we demonstrated
magnetic control of ferroelectric polarization at 432 K in ferroelectric and
ferroelastic Tb$_2$(MoO$_4$)$_3$, in which the polarity of ferroelectric
polarization is coupled to the orthorhombic strain below the transition
temperature 432 K. The paramagnetic but strongly magnetoelastic Tb$^{3+}$
magnetic moments enable the magnetic control of ferroelectric and ferroelastic
domains; the ferroelectric polarization is controlled depending on whether the
magnetic field is applied along [110] or [$\bar{1}$10]. This result may pave a
new avenue for designing high-temperature multiferroics.
