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Spin dynamics in the transition metal oxides La2/3A1/3Mn1-xCoxO3, A = Ca, Sr (0.5 ≤ x ≤1)

I. G. DEAC1,* , R. TETEAN1, E. BURZO1

Affiliation

  1. Faculty of Physics, Babes-Bolyai University 400084 Cluj-Napoca, Romania

Abstract

We present a detailed study of the polycrystalline perovskite system La2/3A1/3Mn1-xCoxO3 A = Ca, Sr (0.5 ≤ x ≤ 1) including electrical resistance, magnetization, ac susceptibility. The static magnetic susceptibility was also measured up to 1000 K. The phase and lattice parameters of the compounds were determined by X-ray powder diffraction. The variation of x will change the relative fraction of both Mn and Co ions spin states. The data suggest the presence of correlated magnetic clusters at low temperatures as confirmed from the frequency dependence of the ac susceptibility and from non-linear ac susceptibility measurements. The electrical resistivity has been measured in the temperature range from 4 K to 300 K in high magnetic fields up to 7 T. The data are analyzed in a in a phase separation scenario..

Keywords

Cobaltites, Manganites, Colossal magnetoresistance, Cluster glas.

Submitted at: Nov. 2, 2006
Accepted at: April 15, 2007

Citation

I. G. DEAC, R. TETEAN, E. BURZO, Spin dynamics in the transition metal oxides La2/3A1/3Mn1-xCoxO3, A = Ca, Sr (0.5 ≤ x ≤1), Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 4, pp. 1108-1112 (2007)