Effects of laser floating zone processing on electrical and magnetic properties of (Ca,Pr)MnO3 system

Abstract

Manganites present fascinating physical properties which can be tuned according with the method and processing conditions. In this work, Ca1-xPrxMnO3 (x = 0.03, 0.06, 0.1) materials were prepared by the Laser Floating Zone (LFZ) technique, under different pulling rates (25–100 mm/h) in air and argon atmospheres, obtaining fibres with 2.5 mm diameter. Such processing conditions promote the formation of secondary phases in (Ca,Pr)MnO3 fibres. The formation of the perovskite phase at slow pulling rates was observed. The effects of the LFZ conditions on the phase composition, microstructural features, electric and magnetic properties of as-grown and thermally post-processed fibres are analysed and discussed. The results indicate that the LFZ processing conditions have a great impact on the electrical and magnetic properties of the prepared manganites. Secondary phases increase with pulling rate and the effects imposed by their formation can be minimized by additional heat treatment at high temperatures, improving the electric conductivity and magnetization of the thermally-treated fibres.