Long-aging effects on the properties of La0.5Sr0.5CoO3−δ films

Abstract

The transport and magnetic properties of as-deposited and long-aged La0.5Sr0.5CoO3−δ films prepared by pulsed laser deposition have been investigated. It was found that an oxygen deficiency in the aged film leads not only to a change in the Co3+:Co4+ ratio, but to the formation of a structural disorder in the Co–O–Co conduction channel due to the accumulated oxygen vacancies. In addition to the usual ferromagnetic transition at TC≃250 K, the second magnetic transition was observed at TM≈50 K, which is treated as a freezing of the spin-glass state provided by the weak disorder in the oxygen arrangement.

Magnetic pair making and breaking effect of Ru in La0.7Sr0.3Mn0.9Ru0.1O3 and La0.5Sr0.5Co0.9Ru0.1O3

“…3) [24]. The square term has been attributed to the electron-electron scattering in manganites [25,26], while the negative square root term is attributed as the Coulomb interaction (CI) effect, which is observed in magnetic disordered systems [27].…”

Oxygen vacancies induced enhancement of photoconductivity of La0.5Sr0.5CoO3 −δthin film

“…Generally, oxygen vacancies in the doped cobaltates would lead to a negative electric charge deficiency which is compensated by a Co 4+ decrease to keep charge neutrality. So the oxygen vacancy will reduce the Co 4+ /Co 3+ ratio to change the mixed Co valence and hole-doping level [24]. The magnetic, transport, and structural properties strongly depend on the hole-doping level [25].…”

Magnetic and transport properties ofLa1−xSrxCoOProkhorov1, Lee2, Kim3 et al. 2002Phys. Rev. BSelf Cite17090View full textAdd to dashboardCite

“…12 On the other hand, the metal-semiconductor ͑or insulator͒ transition in the film could be induced by a reduction in the oxygen content. 10,13,14 The inset of Fig. 2 displays the temperature dependence of the negative MR for the La 1Ϫx Sr x CoO 3 films with the following compositions: ͑1͒ xϭ0.35, ͑2͒ xϭ0.25, and ͑3͒ xϭ0.…”