Low-field colossal magnetoresistance in manganite tunnel spin valves
CEA Saclay, Service de physique de l'état condensé, 91191 Gif-sur-Yvette,
2 UMR CNRS/Thomson-CSF, LCR, domaine de Corbeville, 91404 Orsay Cedex, France
Accepted: 10 July 1997
We report on the magnetoresistive properties of all-oxide tunnel spin valves in which electrodes of mixed valence manganites are separated by a thin insulating layer. The structures were prepared by Pulsed Laser Deposition and several tunnel barriers were used including , and . The latter gives the largest magnetoresistive effect where the trilayer's resistance is increased by a factor of 5.5 at 50 Gauss and 4.2 K. Analysis of the temperature variation of the barrier resistivity shows that the dramatic loss of the magnetoresistive effect above 150 K is due to a reduced oxygen content of the interface between and . Solving this problem should lead to similar results at room temperature.
PACS: 72.15.Gd – Galvanomagnetic and other magnetotransport effects / 75.30.Kz – Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.) / 73.40.Rw – Metal-insulator-metal structures
© EDP Sciences, 1997