Role of A-site deficiency in the magneto-transport properties of Pr<Subscript>0.7</Subscript>Sr<Subscript>0.3</Subscript>MnO<Subscript>3</Subscript> relaxed films

The magneto-transport properties of thick relaxed A-site deficient films having the composition Pr<InlineEquation ID="Equ1"> <EquationSource Format="TEX">$_{0.6}\square_{0.1}$</EquationSource> </InlineEquation>Sr<Subscript>0.3</Subscript>MnO<Subscript>3 </Subscript>(P<Subscript>□</Subscript>SMO with the □ symbol for the Pr vacancy) and Pr<Subscript>0.7</Subscript>Sr<InlineEquation ID="Equ2"> <EquationSource Format="TEX">$_{0.2}\square_{0.1}$</EquationSource> </InlineEquation>MnO<Subscript>3 </Subscript>(PS<Subscript>□</Subscript>MO) are studied. A direct comparison with a Pr<Subscript>0.7</Subscript>Sr<Subscript>0.3</Subscript>MnO<Subscript>3 </Subscript>(PSMO)completely relaxed film, deposited under the same growth conditions, shows a reduction of the in-plane parameter a<Subscript>100</Subscript> associated to an enhancement of the out-plane parameter. The strains (bulk strain ε<Subscript>B</Subscript> and biaxial Jahn-Teller strain ε<Subscript>J-T</Subscript>) do vary with the nature of the cationic vacancy. For example, an enhancement of ε<Subscript>B</Subscript> of 9% in the PS<Subscript>□</Subscript>MO film (Sr deficient) produces a decrease of T<Subscript>C</Subscript> of 30 K, whereas the Pr deficient P<Subscript>□</Subscript>SMO film exhibits a large reduction of both ε<Subscript>B</Subscript> (-16%) and ε<Subscript>J-T</Subscript> (divided by a factor of 5), which enhances T<Subscript>C</Subscript> of 12 K, similarly to previous observations on bulk ceramics. With a reduced resistivity (ρ>0.02 Ω cm), the obtained Pr-deficient film, P<Subscript>□</Subscript>SMO, exhibits the best magneto-transport properties with a decreasing magnetoresistance sensitivity at low field. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2005