Exploring Magnetic XY Behavior in a Quasi-2D Anisotropic Triangular Lattice of Cu(II) by Functionalized Graphene

Abstract

Study on magnetism in two-dimensional (2D) spin–lattices is advancing rapidly. In this work, phase-pure botallackite (Bo) (Cu2(OH)3Br), a quasi-2D S = 1/2 anisotropic triangular spin–lattice is stabilized over 2D reduced graphene oxide (rGO) nanosheets via simple oxidation–reduction reaction chemistry. In comparison to polycrystalline Bo, such an anchoring resulted in the oriented growth of Bo crystallites in the Bo-rGO system. The Bo-rGO nanocomposite was found to be magnetically active with a Néel transition at ∼8.9 K, crossing over to possible XY anisotropy at ∼5 K—as revealed by complementary dc and ac susceptibility measurements—an unprecedented observation in the field assigned to an interfacial effect. This work demonstrates the potential usage of nonmagnetic 2D functionalized graphene to significantly modulate the magnetic properties of 2D spin–lattices.