Type-II antiferromagnetic ordering in the double perovskite oxide Sr2NiWO6

Magnetic double perovskite (DP) compounds provide a fertile playground to explore interesting electronic and magnetic properties. By complementary macroscopic characterizations, neutron powder diffraction measurements, and first-principles calculations, we have performed comprehensive studies on the magnetic ordering in the DP compound ${\mathrm{Sr}}_{2}{\mathrm{NiWO}}_{6}$. It is found by neutron diffraction to order magnetically in a collinear type-II antiferromagnetic (AFM) structure in a tetragonal lattice with $k=(0.5,0,0.5)$ below ${T}_{\mathrm{N}}=56\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. In the ground state, the ordered moment of the spin-1 ${\mathrm{Ni}}^{2+}$ ions is determined to be $1.9(2)\phantom{\rule{0.16em}{0ex}}{\textmu{}}_{\mathrm{B}}$, indicating a significant quenching of the orbital moment. The ${\mathrm{Ni}}^{2+}$ moments in ${\mathrm{Sr}}_{2}{\mathrm{NiWO}}_{6}$ are revealed to cant off the $c$ axis by $29.{2}^{\ensuremath{\circ}}$, which is well supported by the first-principles magnetic anisotropy energy calculations. Furthermore, the in-plane and out-of-plane next-nearest-neighbor superexchange couplings (${J}_{2}$ and ${J}_{2\mathrm{c}}$) are found to play a dominant role in the spin Hamiltonian of ${\mathrm{Sr}}_{2}{\mathrm{NiWO}}_{6}$, which accounts for the stabilization of the type-II AFM structure as its magnetic ground state.