R₂Mo₂O₇pyrochlores under high pressure

Abstract

Currently, we are investigating whether comparable phase transitions with a similar underlying mechanism are also present in the other three compounds.[1]Kanke,Y., Kato, K., Chem. Mater., 1997, 9, 141. [2] Kato, K., Kanke, Y., Friese, K., Z. Krist, 1997, 212, 110. [3] Friese, K., Jarchow, O.,Kato, K, Kanke, Y., Z. Krist., 1997, 212, 859 As promising materials for optoelectronics and with respect to interesting magnetic properties due to competing magnetic sublattices and magnetoelectric interactions, the family of borates RM 3 (BO 3 ) 4 with R = rare earths or Y, La-Lu and M = Al, Ga, Cr, Fe, Sc is of current interest. GdFe 3 (BO 3 ) 4 has been found [1,2] o exhibit a structural phase transition at 156 K, antiferromagnetic order of the magnetic Fe 3+ moments at 36 K, followed by a spin reorientation phase transition at 9 K. Moreover there is evidence for an induced ferroelectric phase in this material in external magnetic fields which demonstrates a strong correlation between the magnetic order and the dielectric properties of GdM 3 (BO 3 ) 4 . Concerning technical applications such compounds, e.g. YAl 3 (BO 3 ) 4 , may be important materials for laser techniques and optical second harmonic generation [3].