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

Abstract

The [Zn 1– x Ni x (HF 2 )(pyz) 2 ]SbF 6 ( 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 MN 4 (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.

Ligand field design enables quantum manipulation of spins in Ni2+ complexes

“…74 The zinc complex, [Zn(ttcn) 2 ](BF 4 ) 2 -$2(MeNO 2 ) crystallizes in the orthorhombic Pbca space group at 295 K, with one independent complex that lies on an inversion center. 75 Variation in lattice parameters and ZFS upon dilution has previously been demonstrated in Ni 2+ quantum magnets as a consequence of anisotropic expansion of M-L bond distances; 76,77 enhanced spin coherence in Cr 4+ spins has also been shown upon dilution. 22 Changes in crystal packing incurred through cooling and dilution in a different symmetry space group for [Zn(ttcn) 2 ] 2+ result in an increase in jDj from 0.60 cm −1 (18 GHz)in 1 to two distinct species in 1 ′ with jDj values of ∼0.9 cm −1 (27 GHz) and ∼1.15 cm −1 (34 GHz), increases of 50% and 110%, respectively, based on simulations of the EDFS spectra (Fig.…”

Percolation-Induced Ferrimagnetism from Vacancy Order in [Gua]Mn1–xFe2x/3(HCOO)3 Hybrid Perovskites

“…But the strongly directional nature of magnetic interactions in Cu 2+ systems, itself a consequence of uneven occupancy of e g * orbitals in d 9 configurations, will likely complicate matters considerablyeven if one ignores the (likely) possibility of interplay between vacancy distributions and orbital order. Such cases may lead to stoichiometry-dependent anisotropy of the kind seen in [Zn 1– x Ni x (HF 2 )­(pyz) 2 ]­SbF 6 , for example . Whatever emerges, our key result here is to have shown how simple chemical modification of a hybrid perovskite can have a profound effect on its magnetic behavior and hence open new avenues for functional materials design that may also be relevant to other inorganic and hybrid perovskite families (such as the Prussian blue analogues) supporting correlated vacancy order …”

“…Such cases may lead to stoichiometrydependent anisotropy of the kind seen in [Zn 1−x Ni x (HF 2 )-(pyz) 2 ]SbF 6 , for example. 35 Whatever emerges, our key result here is to have shown how simple chemical modification of a hybrid perovskite can have a profound effect on its magnetic behavior and hence open new avenues for functional materials design that may also be relevant to other inorganic and hybrid…”

Field- and anisotropy-induced magnetic transitions and specific heat of one-dimensional XYZ ferromagnet with single-ion anisotropy

“…To clarify this crossover behavior in the present model, the components of the specific heat (see (25), (29) and It should be noted that the role of the spin fluctuations cannot be ignored in the 1D models. Therefore, there is a difference in the magnitude of the specific heat when changing a z as stated in figure 11.…”

“…In this article, the functional integral method is used. Besides the exchange anisotropy in the XYZ model, the single-ion anisotropy (SIA) is also taken into account, because the SIA can be tuned in an experiment by using nuclear electric resonance [27], by mechanical control [28], or by atomic substitution [29]. In previous works [11,[30][31][32][33], the functional integral method was used to investigate the thermodynamic properties of the spin systems.…”