Role of A-site deficiency in the magneto-transport properties of Pr0.7Sr0.3MnO3 relaxed films

摘要

The magneto-transport properties of thick relaxed A-site deficient films having the composition Pr(0.6)square(0.1)Sr(0.3)MnO(3)(PsquareSMO with the square symbol for the Pr vacancy) and Pr(0.7)Sr(0.2)square(0.1)MnO(3)(PSsquareMO) are studied. A direct comparison with a Pr0.7Sr0.3MnO3(PSMO) completely relaxed film, deposited under the same growth conditions, shows a reduction of the in-plane parameter a(100) associated to an enhancement of the out-plane parameter. The strains ( bulk strain epsilon(B) and biaxial Jahn- Teller strain epsilon(J-T)) do vary with the nature of the cationic vacancy. For example, an enhancement of epsilon(B) of 9% in the PSsquareMO film (Sr deficient) produces a decrease of T-C of 30 K, whereas the Pr deficient PsquareSMO film exhibits a large reduction of both epsilon(B)(- 16%) and epsilon(J-T) ( divided by a factor of 5), which enhances T-C of 12 K, similarly to previous observations on bulk ceramics. With a reduced resistivity (rho < 0.02 Omega cm), the obtained Pr-deficient film, PsquareSMO, exhibits the best magneto-transport properties with a decreasing magnetoresistance sensitivity at low field.