Effect of Ti ion doping on martensitic transition of La0.5Sr0.5Mn1−xTixO3

Electrical transport and magnetic properties of La0.5Sr0.5Mn1−xTixO3 (x = 0, 0.1, 0.15 and 0.2) have been investigated. Experimental results show that the different Ti4+ doping level has obviously different effect on electrical transport and magnetization properties. Especially, a martensitic transition was observed in higher Ti4+ doping levels (x = 0.15, 0.2). In which a doped Ti4+ ion substitutes a Mn4+ ion, with increasing in Ti4+ doping level from x = 0 to 0.2, the ratio of Mn3+/Mn4+ increases from 1 to 5/3, that is the coupling via Mn3+-O2−-Mn4+ double exchange increases leading to a localized ferromagnetic domain in the charge ordering of matrix of La0.5Sr0.5MnO3. With the increasing of magnetic field to a critical field, the localized magnetic moment was delocalized and rotated to parallel to an applied field showing a martensitic transition.