Magnetic Properties of Metal-Intercalated Layered Vanadyl Phosphates

Abstract

Variable-temperature magnetic susceptibility shows that electrons on the vanadium centers of the Na+, K+, and Rb+ intercalates of layered vanadyl phosphate are ferromagnetically coupled via V(OPO)2V rings within the layers. The superexchange pathway is preserved in the Sr2+-intercalated system, but antiferromagnetic coupling is observed in the intralayer. This disparate behaviour correlates with the orientation of the basal planes of the (VO)O4 subunits in the X-ray-characterized Rb+-intercalated layered phosphate as well as in the previously characterized Na+, K+, and Sr+ systems.

Extension of the spin-12frustrated square lattice model: The case of layered vanadium phosphates

“…Yet, the change of the metal cation bears influence on the magnetic interactions, as indicated by different Curie-Weiss temperatures. 60,62,63,64,65 The magnitude of the frustration in the A(VOPO 4 ) 2 · 4H 2 O compounds remains unknown. All the reports available consider NN interactions only.…”

Analysis and Prediction of Stacking Sequences in Intercalated Lamellar Vanadium Phosphates

“…[11][12][13][14][15]21] These species are localized in "nests" of the interlayer space. [20] For these materials, the interlayer distances range from 6.30 Å for Ca 2+ to 6.76 Å for Na + .…”

“…Lamellar vanadium phosphates are of interest owing to their ability to intercalate organics, [8][9][10] alkali, [11][12][13] alkaline earth metal ions, [14,15] or transition metal (TM) ions. [14,[16][17][18][19] In these compounds, vanadium phosphate layers shift in respect to the adjacent ones with sequences depending on the intercalated species.…”

Magnetic Properties ofM(VOPO4)2· 4H2O (M=Co(II), Ni(II)), Layered Compounds Containing Distinct Magnetic Linear Trimers

“…The presence of readily reducible V(V) ions in this compound allows for the intercalation of a number of metal ions with the parent layered structure maintained (2). Based on the kind of guest cations, such intercalates which share the stoichiometry M(VOPO ) ) nH O can be classified into two types: (i) monovalent metal intercalates, e.g., M(VOPO ) ) nH O (M"Na, K, Rb; n"3, 4) (3,4), where V> is partially reduced to V>, resulting in mixed-valence compounds; (ii) divalent metal intercalates, e.g., M(VOPO ) ) 4H O (M"Ca, Sr, Pb, Ni, Co, Cu) (5-7), where V> is fully reduced to V>. The divalent transition metal intercalates are principally of interest because of their strong tendencies toward coordination.…”

“…Recently, Papoutsakis et al (4) reported an investigation on the magnetic properties of Na>, K>, Rb>, and Sr> compounds. Conclusions were drawn that the bulk ferromagnetic or antiferromagnetic interactions in these compounds correlate with the orientation of the (VO)O intralayer subunits.…”