Giant magnetic domain-wall resistance in phase-separated manganite films

Abstract

The top and bottom electrodes of the ferromagnetic manganite La 0.7 Ca0.3 MnO3 may be magnetically decoupled by a La0.59 Ca0.41 MnO3 interlayer in which ferromagnetic and paramagnetic phases coexist. In mesas fabricated from these trilayer films, in-plane magnetic domain walls associated with the antiparallel magnetic electrode configuration show a giant resistance-area product > 10-10 m2. This is almost two orders of magnitude larger than our devices with interlayer composition La0.6 Ca0.4 MnO3 [C. Israel, Phys. Rev. B 78, 054409 (2008)] where phase separation is less extreme. High-field treatments modify the ferromagnetic phase fraction of the interlayer.