Magnetic field driven transition from an antiferromagnetic ground state to a ferrimagnetic state in Rb_0.19Ba_0.3Mn_1.1[Fe(CN)₆]·0.48H₂O Prussian blue analogue

We report a magnetic field dependent (H) antiferromagnetic (AFM) to ferrimagnetic (FIM) transition in Rb0.19Ba0.3Mn1.1[Fe(CN)6]·0.48H2O Prussian blue analogue. A microscopic understanding of the nature of this field induced AFM to FIM transition is achieved by carrying out a low temperature neutron diffraction study under an external magnetic field. A decrease in Néel temperature and an evolution of a ferrimagnetic phase with an increase in dc magnetic field are evident in dc magnetic field dependent ac susceptibility measurements. With an increase in H, the FIM phase grows at the expense of the AFM phase, and for H > 4 T, the system fully transforms to the FIM phase. A magnetic structure consisting of an antiparallel stacking of ferrimagnetic sheets along crystallographic c-direction is proposed for the FIM phase. Based on the results obtained, a phase diagram describing the evolution of both magnetic phases under external magnetic field is presented