NMR/NQR studies of TbCoGa

Saito, Yo; Sakai, Hironori   ; Tokunaga, Yo  ; Kambe, Shinsaku  

TbCoGa composed of the tetragonal HoCoGatype structure(D-P4/mmm) was reported that it has below the upper critical temperature T and above the lower critical temperature T, and shows unusual successive phase transitions. Generally, systems caused successive phase transitions are origin of the geometrical frustration of exchange interactions between spins of magnetic ions. (Ex. triangular lattice antiferro magnets CsNiCl) But, the tetragonal compound TbCoGa was thought that it's not caused the geometrical frustration. Therefore, TbCoGa is considered to be a new mechanism different from the geometrical frustration of triangular lattice antiferro magnets. For example, there is competition of magnetic interactions and quadrupolar interactions in f-Electron systems.