抄録
We examined electroresistive effects of epitaxial La0.67Ca0.33MnO3(LCMO) thin films deposited on LaAlO3(100)(LAO) substrates. The films are under compressive strain due to lattice mismatch between LCMO (a ≈ 3.86 Å) and LAO (a ≈ 3.79 Å). To relax this strain, our films appear to consist of regions of high-strained charge-ordered insulator (COI) and low-strained ferromagnetic metal (FMM) at low temperatures. By using a micro-fabricating process to the samples, large current density can be applied effectively. These mixed-phase inhomogeneous thin films showed an interesting current-induced first-order transition from COI to FMM. This non-reversible behavior is pronounced with increasing maximum applied current. These results strongly suggest that spin-polarized electrons in FMM are injected into COI; as a result, antiferromagnetic localized electron spins are forced to align ferromagnetically.
