Structural and magnetic phases of rare-earth disilicates, R₂Si₂O₇

Rare-earth disilicates are interesting due to the variety of physical properties that they exhibit. The rich range of magnetic behaviors originates in the polymorphism exhibited by these materials. Recent reports showing that Yb₂Si₂O₇ exhibits a quantum dimer magnet state motivated us to embark upon the investigation of some less-studied disilicate compounds, R₂Si₂O₇ (R = Er, Ho and Tm). Previous studies show that Er₂Si₂O₇ orders antiferromagnetically below T_N = 1.9 K, as well as exhibiting a highly anisotropic magnetic behavior, however, the magnetic ground state of this compound is not yet established. To date, the magnetic properties of Ho₂Si₂O₇ and Tm₂Si₂O₇ have not been reported. Here, we present the results of our investigations to optimize the synthesis and crystal growth conditions of R₂Si₂O₇ (R = Er, Ho and Tm), and also discuss the structural and magnetic properties of these materials.