Linear and nonlinear susceptibilities of rare earth ferroic molybdates

We have measured the linear and nonlinear susceptibilities of several mixed rare earth molybdates Ln2xGd2(1−x)(MoO4)3, where Ln is Nd, Sm, Gd, Tb, Ho, Yb. We conclude that the major part of the nonlinear optical properties is due to the MoO4 tetrahedra orientation and to the Mo–O bond hyperpolarizability. Extrapolated linear and nonlinear polarizabilities of pure compounds Ln2(MoO4)3 agree with the instability of Yb, Tm, and Er ferroic molybdates.