We report the magnetic and electronic structures of the inverse-trirutile compound $\mathrm{C}{\mathrm{r}}_2\mathrm{Mo}{\mathrm{O}}_6$. Despite the same crystal symmetry and similar bond lengths and bond angles as $\mathrm{C}{\mathrm{r}}_2\mathrm{Te}{\mathrm{O}}_6,\mathrm{C}{\mathrm{r}}_2\mathrm{Mo}{\mathrm{O}}_6$ possesses a magnetic structure different from that in $\mathrm{C}{\mathrm{r}}_2\mathrm{Te}{\mathrm{O}}_6$. ab initio electronic structure calculations show that the sign and strength of the Cr-O-Cr superexchange coupling is strongly influenced by the hybridization between the filled $\mathrm{O}2p$ and empty $\mathrm{Mo}4d$ orbitals: the virtual transfer of an $\mathrm{O}2p$ electron to the empty $\mathrm{Mo}4d$ orbitals leaves the $\mathrm{O}2p$ partially occupied, which leads to ferromagnetic exchange between Cr moments. This result further substantiates our recently proposed mechanism for tuning the exchange interaction between two magnetic atoms by modifying the electronic states of nonmagnetic atoms in the exchange path through orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.

• Received 20 January 2015
• Revised 24 March 2015

DOI:https://doi.org/10.1103/PhysRevB.92.094419