Exchange and dipolar interactions in PrVO4: Gd

Electron paramagnetic resonance of the Van Vleck compound PrV${\mathrm{O}}_4$ doped with Gd has been used to study the exchange and dipolar interactions of the ${\mathrm{Pr}}^{3+}$-${\mathrm{Gd}}^{3+}$ pair. The ${\mathrm{Gd}}^{3+}$ electronic $g$ shifts depend only on the diagonal components of these interactions. The pseudoaxial fields and the indirect superhyperfine interactions are functions of both diagonal and off-diagonal elements. From a combined measurement of all these interactions, both symmetric and antisymmetric exchange fields can be estimated.