tailieunhanh - Structure and properties of double perovskite system La2Co1−xFexMnO6

Low Fe-doped insulating ferromagnets La2CoMnO6 were prepared and studied. The compounds crystallized in orthorhombic space group Pnma with slight changes in the lattice constants. We have observed a significant reduction of resistivity due to doping, together with an increase of magnetization and saturated magnetization as doping level increased. The doping also reduced TC for both transitions at around 220 and 140 K which attribute for the different spin orderings of the magnetic ions. The small features were also seen at around 40 K and should correspond to the cluster glassy region with spin disorders. | Communications in Physics, Vol. 24, No. 3S1 (2014), pp. 80-84 DOI: STRUCTURE AND PROPERTIES OF DOUBLE PEROVSKITE SYSTEM La2 Co1−x Fex MnO6 PHAM THE TAN Faculty of Basic Science, Hung Yen University of Technology and Education, Hung Yen, Vietnam PHAM HUYEN YEN AND HOANG NAM NHAT Faculty of Technical Physics and Nanotechnology, University of Engineering Technology, Vietnam National University, Hanoi NGUYEN QUANG HOA Faculty of Physics, Hanoi University of Science, Vietnam National University, Hanoi, Vietnam E-mail: phamthetansp@ Received 20 June 2014 Accepted for publication 20 August 2014 Abstract. Low Fe-doped insulating ferromagnets La2 CoMnO6 were prepared and studied. The compounds crystallized in orthorhombic space group Pnma with slight changes in the lattice constants. We have observed a significant reduction of resistivity due to doping, together with an increase of magnetization and saturated magnetization as doping level increased. The doping also reduced TC for both transitions at around 220 and 140 K which attribute for the different spin orderings of the magnetic ions. The small features were also seen at around 40 K and should correspond to the cluster glassy region with spin disorders. Keywords: Structure, Magnetism, Fe-doped, La2 CoMnO6 . I. INTRODUCTION The ferroelectric insulators of a form RE2 AMnO6 where RE is a rear earth element and A a transition metal attract a lot of interests due to a co-existence of ferromagnetism and insulating state within a single structural frame [1,2]. Among the effects that were found in these double perovksites is the dependence of dielectric permitivity on magnetic field which promises direct application in spintronics as the magnetic field driven capacitors. The double perovskites inherits from the single ones a structural type that is built up from the connecting MnO6 polyhedrons, but here the polyhedrons are connected only in (x, y) plane and in the (z) direction one .