Magnetically Controllable Cooperative Jahn-Teller Distortion in TmAsO4

Abstract

TmAs${\mathrm{O}}_{4}$ undergoes a cooperative Jahn-Teller distortion at 6.0 K. At $Tl6$ K there is a temperature-dependent critical field ${\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}}_{c}$ at which a cooperative distortion back to the high-temperature phase occurs. For $Bl{B}_{c}$, the distortion directions in the basal plane are the (110) and the ($1\overline{1}0$) directions and are magnetically controllable.