EPR in Kagome Staircase Compound Mg_2.997Co_0.003V₂O₈

Abstract

The paramagnetic resonance of Co 2+ ions in Mg2.997Co0.003V2O8 single crystals are reported. The EPR spectrum shows two groups of resonance lines associated with two crystallographically nonequivalent Co ions positions that are known in the kagome staircase system as "cross-tie" and "spine" sites. No preferential occupation of Co 2+ ions in the kagome lattice was observed. The ground state was described by spin-Hamiltonian with an effective electronic spin S = 1/2 and nuclear spin I = 7/2. The local symmetry of oxygen octahedron surrounding Co ions, main values of the g-factors, and hyperfine structure were determined for both cobalt positions.

Magnetic anisotropy in geometrically frustrated kagome staircase lattices

“…[20,21]) nevertheless, the results obtained confirm significant contribution of single-ion mechanism to the effective magnetic anisotropy in Co 3 V 2 O 8 single crystals.…”

“…The results yielded, Another (indirect) way to determine crystal field parameters acting on magnetic ions is to study the electron paramagnetic resonance (EPR) spectra of magnetically diluted kagome staircase compounds. We have performed such measurements for Mg 3 V 2 O 8 doped with 0.3% Co [20]. The EPR spectrum shows two groups of resonance lines associated with Co ions in spine sites and cross-tie sites.…”

Effect of Chemical Disorder on Geometrically Frustrated Kagome Lattice

“…It is due to the orbital contribution to the overall moment which is not quenched (in such case p eff = 6.64µ B /Co 2+ ). The anisotropy of p eff is in agreement with EPR measurements performed on Mg 2.997 Co 0.003 V 2 O 8 single crystals [34] and suggests that the main contribution to χ(T ) arises due to the Co 2+ spine sites.…”

EMR-related problems at the interface between the crystal field Hamiltonians and the zero-field splitting Hamiltonians

“…(1) Confusion between the CF (LF) and SH (ZFS) quantities, mainly the CF=ZFS confusion exemplifi ed by consideration of the two notions: the CF parameters (CFPs) and the ZFS parameters evidently as synonymous, occurs in recent EMR--related papers, e.g., [22][23][24][25][26][27][28][29][30][31][32]; for critical comments, see [14]. Apart from the problems and confusions identifi ed in the review on molecular magnets [16], serious forms of the CF=ZFS confusion occur also in the EMR and SMM/MNM related textbook [13].…”