Koushik Karmakar

Abstract:

CuLa2Ge2O8 forms a distorted triangular lattice of quantum spin-1/2 Cu²⁺ ions. A crystal growth method was developed using the traveling-solvent floating zone technique, resulting in the synthesis of a large single crystal (4mm×4mm×10 mm). The crystal was characterized with regard to phase purity and crystallinity using powder x-ray diffraction, energy dispersive x-ray analysis, and Laue diffraction, and found to be of excellent quality. The magnetic properties were characterized using dc-susceptibility, magnetization, and heat capacity measurements, which revealed weak magnetic frustration with long-range magnetic order occurring below TN=1.14(1) K. The magnetic structure determined using neutron powder diffraction is a commensurate, noncollinear antiferromagnetic structure, different from the 120^∘ order of an equilateral triangular antiferromagnet. The ordered moments lie in the bc-plane, with components mb=0.50(3) µB and mc=0.73(5) µB along the b- and c-axes respectively, giving a total ordered moment of Mtotal=0.89(6)µB/Cu²⁺ at 20 mK.