We have measured magnetic and transport response on the polycrystalline ${\mathrm{La}}_{5/8-y}{\mathrm{Pr}}_y{\mathrm{Ca}}_{3/8}{\mathrm{MnO}}_3$ $(y=0.30,$ average grain size 2 microns) compound. In the temperature range where ferromagnetic metallic and insulating regions coexist, we observed a persistent memory of low magnetic fields $(<\mathrm{}1\mathrm{}\hspace{0.5em}\mathrm{T})$ that is determined by the actual amount of the ferromagnetic phase. The possibility to manipulate this fraction with relatively small external perturbations is related to the phase-separated nature of these manganese-oxide-based compounds. The colossal magnetoresistance figures obtained (about 80%) are determined by the fraction enlargement mechanism. Self-shielding of the memory to external fields is found under certain described circumstances. We show that this nonvolatile memory has multilevel capability associated with different applied low magnetic-field values.

• Received 28 December 2001

DOI:https://doi.org/10.1103/PhysRevB.65.140401