Electron-paramagnetic-resonance spectrum of an exchange-coupledCr3+-Mo3+pair

When crystals of CsMg${\mathrm{Cl}}_3$ are doped with ${\mathrm{Cr}}^{3+}$ and ${\mathrm{Mo}}^{3+}$ a significant concentration of an exchange-coupled ${\mathrm{Cr}}^{3+}$-${\mathrm{Mo}}^{3+}$ pair is produced. The electron-paramagnetic-resonance spectrum of the mixed pair is well described by a rather straightforward spin Hamiltonian. The exchange interaction is approximately 1.6 ${\mathrm{cm}}^{-1\mathrm{}}$ and appears to be antiferromagnetic.