Engineering of ion-doping on the ground states and Bose–Einstein condensation of Sr 3 Cr 2 O 8

Single crystals of Sr 3 Cr 2 O 8 , Sr 3 Cr 1.9 V 0.1 O 8 and Sr 3 Cr 1.9 Fe 0.1 O 8 were grown using the floating zone technique, and their magnetization behaviors were systematically investigated under pulsed field up to 54 T at various temperatures ranging from 2 K to 20 K. Temperature-induced transition from singlet ground state to triplet state and magnetic-field-induced Bose–Einstein condensation were observed, of which the critical temperature and the critical field are correlative to ion-dopants. The analysis of the ground state and low-field magnetization behaviors indicates that the ion-dopants lead to an enhancement of the intradimer exchange J 0 , which changes the transition temperatures, and increases the critical fields H c1 . The magnetic Fe ion dopant makes the transition from singlet to triplet states more sensitive to the applied magnetic field, in clearly contrast to the situation of the nonmagnetic V 5+ dopant.