Thermodynamics of strongly frustrated magnet in a field: Ising antiferromagnet on triangular Husimi lattice

Some strongly frustrated magnets such as the "spin-ice" compounds fail to produce any magnetic order at finite temperatures even in the presence of magnetic field. Still they have very unusual low-temperature thermodynamic properties related to the field-induced ground state transitions. Here we show that general qualitative picture of such peculiar thermodynamics can be obtained in the antiferromagnetic Ising model on the triangular Husimi lattice. The analytical results for this model show magnetic plateaus, entropy spikes, crossing points and peculiarities in magnetic susceptibility and specific heat behavior reflecting the existence of ground state transitions. These signatures of strong frustration may help in search of new frustrated magnets and in the interpretation of experimental data.