  The origin of the resistivity minimum observed in strongly phase separated
manganites has been investigated in single crystalline thin films of LPCMO
(x~0.42, y~0.40). The antiferromagnetic/charge ordered insulator
(AFM/COI)-ferromagnetic metal (FMM) phase transition, coupled with the colossal
hysteresis between the field cool cooled and field cooled warming magnetization
demonstrates strongly phase separated nature, which gives rise to
non-equilibrium magnetic liquid state that freezes into a magnetic glass. The
thermal cycling and magnetic field dependence of the resistivity unambiguously
shows that the pronounced resistivity minimum observed during warming is a
consequence non-equilibrium states resulting from the magnetic frustration
created by the delicate coexistence of the FMM and AFM/COI phases. The
non-equilibrium states and hence the resistivity minimum is extremely sensitive
to the relative fraction of the coexisting phases and can be tuned by intrinsic
and extrinsic perturbations like the defect density, thermal cycling and
magnetic field.

Materials Science