Field-induced avalanche to the ferromagnetic state in the phase-separated ground state of manganites

Perovskite manganite compounds such as Pr_(1-x)(Ca_(1-y)Sr_y)_xMn3 can be tuned to exhibit a metastable ground state where two magnetic/crystallographic phases coexist in zero magnetic field. Field-dependent neutron diffraction measurements on both poly- and single-crystal samples with a range of Pr, Ca, and Sr dopings(0.3<x<0.35 and y<0.30) reveal that the charge-ordered, antiferromagnetic phase of the ground state suddenly and irreversibly jumps to the ferromagnetic state. The transition occurs spontaneously at some time after the field is set above a threshold field, indicating that once the transition is initiated an avalanche occurs that drives it to completion.