Long range ferromagnetic ordering in pulsed laser deposited La0.7Ca0.3Mn1−xRuxO3 thin films

Abstract

We demonstrate the existence of the metal to insulator transition (T_MIT) up to 30% of Ru substitution at the Mn site, while the ferromagnetic transition (T_C) is sustained even beyond 30% Ru substitution in the pulsed laser deposited La_0.7Ca_0.3Mn_1−xRu_xO₃ thin films. The presence of Ru(IV) and (V) states complementing the t_2g and e_g orbital parentage of Mn(III) and Mn(IV) brings about prolonged double exchange mediated magnetic and electronic interactions, as confirmed by the X-ray absorption spectra and a negative magneto resistance ratio (MR) up to 11% at T_MIT even for 30% Ru substitution.