Geometrically Frustrated Kagome Lattice with Chemical Disorder

Abstract

One of the most studied geometrically frustrated systems is the twodimensional kagome lattice. Recently, the isostructural compounds M3V2O8 (M = Ni, Co, Cu, Mg) were shown to be new variants of the kagome lattice [1–11]. Among them the most frequently studied of the M3V2O8 systems have been Ni3V2O8 and Co3V2O8. Despite these materials having identical crystal symmetry and similar structural parameters, their magnetic properties are quite different. The difference between the two materials may, in part, be attributed to the magnetocrystalline anisotropy, which is found to be far larger in Co3V2O8 than in Ni3V2O8 [6]. The magnetic behavior of these materials may be described in terms of two inequivalent magnetic ion sites, known as spine sites and crosstie sites. The ordering in both materials involves spin component aligned along the a-direction. The magnetic structure always involves ordering of the spine spins. Magnetic susceptibility, neutron diffraction and specific heat measurements revealed that both Ni3V2O8 and Co3V2O8 undergo a series of magnetic phase transitions versus temperature and magnetic field. Recently, we have studied [12] the phase diagram of cobalt-doped geometrically frustrated Ni3V2O8 single crystals. This paper is a continuation of the studies presented in [12] focused on crystal field effects in pure and doped kagome systems.