Half Metallicity in Pr$_{0.75}$Sr$_{0.25}$MnO$_3$: A first Principle study

In this communication we present a first principle study of Pr$_{1-x}$Sr$_{x}$MnO$_3$ with $x = 0.25$. While the parent compounds of this system are antiferromagnetic insulators with different structural and magnetic ground states, the $x = 0.25$ is in the colossal magnetoresistance regime of the Pr$_{1-x}$Sr$_{x}$MnO$_3$ phase diagram [C. Martin, A. Maignan, M. Hervieu, B. Raveau, Phys. Rev. B 60 (1999) 12191]. Our band structure calculations for the end-point compounds matches well with the existing theoretical and experimental results [C. Martin, A. Maignan, M. Hervieu, B. Raveau, Phys. Rev. B 60 (1999) 12191; Rune Sondena, P. Ravindran, Svein Stolen, Tor Grande, Michael Hanfland, Phys. Rev. B 74 (2006) 144102]. Interestingly, our calculations show that the Pr$_{0.75}$Sr$_{0.25}$MnO$_3$ has a half-metallic character with a huge band gap of 2.8 eV in the minority band. We believe this result would fuel further interest in some of these special compositions of colossal magnetoresistive manganites as they could be potential candidates for spintronic devices. We discuss the half-metallicity of the Pr$_{0.75}$Sr$_{0.25}$MnO$_3$ in the light of changes in the orbital hybridization as a result of Sr doping in PrMnO$_3$. Further, we highlight the importance of half-metallicity for a consolidated understanding of colossal magnetoresistance effect.