Investigations into the tunneling magnetoresistance effects in thin films of (La1−yPry)1−xCaxMnO3
Abstract
Thin lms of (La1−yPry)1−xCaxMnO3 (LPCMO) are known to undergo phase separation between
a ferromagnetic metallic (FMM) phase and a charged-ordered insulator (COI) phase. When cooled
down from room temperature to achieve this phase separation, it appears that the FMM regions can
move through the COI regions as if they were in a
uid, which is known as the
uid phase separated
(FPS) state. By manipulating the FMM regions in the FPS state using magnetic and electric elds,
one can achieve tunneling magnetoresistance (TMR) e ects desirable for the creation of magnetic
tunnel junctions (MTJs), which are useful for data storage. In this investigation, two di erent
LPCMO samples were fabricated, one with metal contacts separated by a few millimeters (the
\millimeter" sample) and another with contacts separated by a few micrometers (the \micrometer"
sample). It was observed that TMR e ects were present in the \micrometer" sample, but not in the
\millimeter" sample, indicating that the \micrometer" sample is more useful than the \millimeter"
sample for the creation of MTJs. In addition, electric eld e ects on TMR were observed, but are
not yet fully understood.