Fifty-nanometer thick (100) and (101) VO$ _{2}$ films were synthesized on C-plane and R-plane Al$ _{2}$O$ _{3}$ substrates using pulsed laser deposition. X-ray diffraction measurements suggested that the VO$ _{2}$ films with a root-mean-square roughness of 0.58 -- 1.08 nm had good crystalline properties. The temperature dependence of the resistance for the VO$ _{2}$ films displayed a metal-insulator transition behavior at T$ _{\text{MI}}$= 325 -- 350 K. Co/Pt multilayers with perpendicular magnetic anisotropy were deposited on (100) and (101) VO$ _{2}$ film by using DC sputtering, and their magnetic properties were monitored by using magneto-optic Kerr effect measurements. Although the VO$ _{2}$ has a structural transition from monoclinic to tetragonal at the T$ _{\text{MI}}$, the (100) VO$ _{2}$ plane seems to have opposite changes in the two in-plane lattice constants, so no net strain is induced in the neighboring Co/Pt film. On the other hand, the (101) VO$ _{2}$ with net changes in both in-plane lattice constants at the T$ _{\text{MI}}$ presumably provides interfacial stress to the neighboring Co/Pt film thus, it induces a net magnetoelastic effect, which results in an increases in the coercive fields of ~ 5 Oe along the easy axis and ~200 Oe along the hard axis.

Keywords: Vanadium oxide, Magnetic film, Perpendicular magnetic anisotropy