The study of nearest- and next-nearest-neighbour magnetic interactions in seven tetragonal compounds V(IV) containing linear chains and square lattices

TL;DR

This study uses a new crystal chemical method to analyze both nearest- and next-nearest-neighbor magnetic interactions in seven tetragonal V(IV) compounds, revealing complex geometries and frustration effects influenced by slight structural displacements.

Contribution

It introduces a novel method for calculating magnetic interactions in tetragonal compounds, considering both NN and NNN interactions based on structural data, and uncovers diverse magnetic geometries and frustration phenomena.

Findings

Magnetic interactions are highly sensitive to small displacements of XO4 groups.

Multiple geometrical configurations, including chains and lattices, were identified.

All studied compounds exhibit magnetic frustration.

Abstract

A new crystal chemical method was used to calculate the sign and strength not only of the nearest-neighbor (NN)interactions, but also of the next-nearest-neighbor (NNN) ones in tetragonal compounds Zn2(VO)(PO4)2 (I),(VO)(H2PO4)2 (II), (VO)SiP2O8 (III), (VO)SO4 (IV), (VO)MoO4 (V), Li2(VO)SiO4 (VI) and Li2(VO)GeO4 (VII) with similar sublattices of V4+ ions on the basis of the room-temperature structural data. The reason for difference between respective magnetic interactions characteristics of these compounds was established. It is shown that the characteristic feature of these compounds is a strong dependence of the strength of magnetic interactions and the magnetic moments ordering type on slight displacements of XO4 (X = P, Mo, Si or Ge) groups even without change of the crystal symmetry. In addition to extensively studied square lattice, other specific geometrical configurations of V4+ were discovered. These configurations can result in frustration of magnetic interactions, namely linear chains along the c-axis with competing nearest- and next-to-nearest-neighbor interactions; rectangular (in I) and triangular (in II-VII) lattices with non-equivalent nearest-to-neighbor interactions, which can be also considered as n-leg ladders; one extra square lattice in the ab-plane with longer range interactions. It was concluded that virtually all magnetic interactions in these compounds were frustrated.