Effect of the Cr5+ ion doping on the quantum transition of the spin-dimer compounds Ba3Mn2-xCrxO8 (x=0, 0.01, 0.04 and 0.06)

Ba3Mn2O8 has a quantum-disordered paramagnet ground state formed by the singlet, and the excitation states with the triplon and quintuplet. We have investigated the magnetization behaviors of the single crystal samples Ba3Mn2-xCrxO8 (x = 0, 0.01, 0.04 and 0.06) with both the static and pulsed high magnetic field from zero up to 60 T. At the temperature T-N, the magnetization decreases rapidly with the decrease of temperature, which is the evidence of the dimerization of spin dimers. The field-induced quantum magnetization plateaus (half of the saturation magnetization) and high-field polarization states show the excited triplet and quintuplet states appear with the change of temperature and the applied magnetic field. The high field magnetization and ESR measurement results confirm that the J(0)/k(B) value and the zero-field gap Delta/k(B) value are close to the reported value, which also indicates that Ba3Mn2-xCrxO8 is not a simple isolated dimer system.