Magnetic frustration on a Kagomé lattice in R3Ga5SiO14 langasites with R = Nd, Pr

摘要: In the R3Ga5SiO14 compounds, network R of rare earth cations forms well separated planes corner sharing triangles topologically equivalent to a Kagome lattice. Powder samples and single crystals with = Nd Pr were prepared magnetostatic measurements performed under magnetic field up 10 T in temperature range from 1.6 400 K. Analysis susceptibility at high temperatures where only quadrupolar term crystal electric prevails suggests that moments can be modelled as coplanar elliptic rotators perpendicular threefold axis structure interact antiferromagnetically. Nonetheless, disordered phase ascribed geometric frustration persists down lowest temperature, which is about 25 times smaller than energy scale for exchange interactions.