• 
  Troyanchuk, I.O.; Karpinsky, D.V.; Lobanovsky, L.S.; Franz, A.; Silibin, M.V.; Gavrilov, S.A.: Magnetic properties and magnetoresistance in La_0.5Sr_0.5Co_1-xMe_xO₃ (Me = Cr, Ga, Ti, Fe) cobaltites. Materials Research Express 3 (2016), p. 016101/1-7

10.1088/2053-1591/3/1/016101

Abstract:
Magnetic and magnetotransport properties of stoichiometric cobaltites La0.5Sr0.5Co1−xMexO3 (Me = Cr, Ga, Ti, Fe, x ≤ 0.25) have been investigated by neutron powder diffraction, magnetization and electrical measurements in fields up to 14 T. It is shown that doping with Fe up to x = 0.2 slightly increases magnetization herewith the Curie point decreases. The chromium doping leads to dramatic decrease of magnetization and the Curie point, associated coherent magnetic contribution in NPD patterns quickly decreases with doping and becomes nearly negligible for x = 0.2 compound. The substitution with diamagnetic Ga and Ti ions decreases the magnetization to a lesser extent than in the chromium doped compound. The Cr, Ti and Ga substitution leads to a strong increase in magnetoresistance at low temperature as compared with undoped cobaltite. The obtained results indicate that the magnetic interactions between Co and Fe are positive whereas those between Co and Cr ions are negative. Enhancement of magnetoresistance is attributed to the magnetic field induced transition from local antiferromagnetic order to ferromagnetic one.