Controlling Magnetic Anisotropy in a Zero-Dimensional S=1 Magnet Using Isotropic Cation Substitution

The [Zn1-xNix(HF2)(pyz)(2)]SbF6 (x = 0.2; pyz = pyrazine) solid solution exhibits a zero-field splitting (D) that is 22% larger [D = 16.2(2) K (11.3(2) cm(-1))] than that observed in the x = 1 material [D = 13.3(1) K (9.2(1) cm(-1))]. The substantial change in D is accomplished by an anisotropic lattice expansion in the MN4 (M = Zn or Ni) plane, wherein the increased concentration of isotropic Zn(II) ions induces a nonlinear variation in M-F and M-N bond lengths. In this, we exploit the relative donor atom hardness, where M-F and M-N form strong ionic and weak coordinate covalent bonds, respectively, the latter being more sensitive to substitution of Ni by the slightly larger Zn(II) ion. In this way, we are able to tune the single-ion anisotropy of a magnetic lattice site by Zn-substitution on nearby sites. This effect has possible applications in the field of single-ion magnets and the design of other molecule-based magnetic systems.

Automated summary

The study shows that tuning the single-ion anisotropy of a magnetic lattice site by Zn-substitution on nearby sites can significantly change the zero-field splitting. This approach has potential applications in the design of single-ion magnets and other molecule-based magnetic systems.