Dielectric Study on the Phase Transitions in Deuterated Tetramethylammonium Trichloromanganate N(CD_3)_4MnCl_3 (DTMMnC)

Abstract

The low-temperature phase transition in N(CD₃)₄MnCl₃ (DTMMnC)has been studied by dielectric measurements. The transitiontemperature of DTMMnC is 126.4 K at zero pressure, which is almostunchanged from that of the normal compound N(CH₃)₄MnCl₃(TMMnC). The effect of deuteration on the pressure-temperature phasediagram is also insignificant: the deuteration lowers the criticalpressure at which the pressure-induced phase (Phase III) appears byabout 10 MPa. The isotope-effect is compared with that in[N(CH₃)₄]₂MnCl₄-type compounds and discussed.