Enhanced Nuclear Cooling And Spin-Lattice Relaxation-Time In Tmvo4 And Tmpo4

Adiabatic demagnetization experiments were performed on hfs enhanced nuclear systems, TmVO 4 and TmPO 4 . The minimum temperatures reached were about 0.1 mK for TmVO 4 and 0.4 mK for TmPO 4 . Temperature and magnetic field dependences of the spin-lattice relaxation time of TmVO 4 and TmPO 4 were measured in the temperature range from 20 mK to 2 K.