Neutron Scattering and Thermodynamic Studies of Low Spin Kagome Magnets

Materials containing low quantum number spins arranged on a kagome lattice are some of the most promising candidates to display spin liquid ground states due to the high degree of geometric frustration. Cu(1,3-bdc) is a hybrid organometallic compound featuring antiferromagnetically coupled S=$\frac{1}{2}$ Cu$^{2+}$ ions on a kagome lattice. Below T=1.8 K the magnetic moments enter a quasi-static phase with no long range magnetic order but extremely slow spin fluctuations. Application of a magnetic field quickly leads to a competing magnetic phase, with a 1 Tesla field able to completely polarize the magnetization below T=2 K. We present inelastic neutron scattering measurements of Cu(1,3-bdc) and note the emergence of low-energy modes in the quasi-static phase. We also present new thermodynamic data on the compound BaNi$_{3}$(OH)$_{2}$(VO$_{4}$)$_{2}$, recently synthesized by our group, which features S=1 Ni$^{2+}$ ions on a kagome lattice.