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Abstract
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The impact of pulse repetition rate and film thickness on the magnetic, magnetoresistance
(MR) and anisotropic magnetoresistance (AMR) has been investigated for
La0.4Pr0.3Ca0.3MnO3 thin films grown on LaAlO3 (LAO) substrates by pulsed laser
deposition technique. Change in repetition rate led to a difference in growth modes
and altered the magnetic and electrical properties (MR and AMR) of thin films. The
XRD results show that in the films with the thickness of 100 nm, by increasing the
pulse repetition rate from 2 to 7 Hz the strain level doesn’t change, while strain
significantly increased at the repetition rate of 10Hz. Analysis of transport and magnetization
measurements show that at 2 and 5 Hz deposited films, the ferromagnetic
metallic behavior is dominant, while in the film deposited at 10 Hz the antiferromagnetic
(AFM) insulating phase increased. Moreover, with increasing strain in the
thinner films (40 nm), deposited at 2 Hz, AFM phase is strengthened. Exchange bias
confirms the existence of a dead layer in 100 nm film deposited at 10 Hz and 40 nm
film deposited at 2 Hz. In addition, high strain in thinner films led to an enhanced
Jahn-Teller coupling, so the angular momentum and spin-orbital/lattice interactions
are significantly increased, which led to a lower magnetoresistance in thinner films.
These results suggest that the pulse repetition rate provides an additional degree of
freedom to tune magnetic and electrical properties of manganite thin films prepared by
pulsed laser deposition technique.
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