Abstract
is a novel two-dimensional antiferromagnet with randomly depleted square lattice. The crystal structure contains two types of square planes with different substitution rates (20% and 40%). NMR and magnetization measurements performed on single crystals of revealed the occurrence of magnetic order at and the change of the magnetic state at . The high-temperature transition can be attributed to establishment of magnetic order in planes with higher concentration of magnetic ions and the low-temperature transition to the magnetic ordering in planes with lower concentration of magnetic ions. Broad continuous NMR spectra below reflect a continuous distribution of values or directions of magnetic moments in typical for spiral, spin-modulated magnetic structures or structures with frozen disorder. Magnetization measurements revealed a spin-flop transition which indicates weak uniaxial anisotropy of the spin structure. The relatively small magnetic susceptibility at all orientations of applied magnetic field shows that the magnetic structure is rigid since the estimated value of saturation field derived from differential susceptibility measured at is .
5 More- Received 20 December 2023
- Accepted 28 February 2024
DOI:https://doi.org/10.1103/PhysRevB.109.115151
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