The effect of cation disorder on magnetic properties of new double perovskites La2NixCo1-xMnO6 (x=0.2-0.8)

JOURNAL OF ALLOYS AND COMPOUNDS

卷:778

Article

Harbi, A.¹  Moutaabbid, H.²  Li, Y.³  Renero-Lecuna, Carlos⁴  Fialin, M.⁵  Le Godec, Y.²  Benmokhtar, S.¹  Moutaabbid, M.¹ 

[1] Univ Casablanca, Fac Sci, Dept Chem, LCPM, Casablanca, Morocco

[2] Sorbonne Univ, Inst Mineral & Phys Mat & Cosmochim, 4 Pl Jussieu, F-75005 Paris, France

[3] Sorbonne Univ, Inst Parisien Chim Mol, CNRS, UMR 8232, 4 Pl Jussieu, F-75252 Paris, France

[4] Univ Cantabria, Fac Med, Grp Nanomed, IDIVAL, Avd Cardenal Herrera Oria S-N, Santander 39011, Spain

[5] Inst Phys Globe, CNRS, UMR7154, Serv Camparis, Paris, France

关键词: Double perovskites;    Spin glass transition;    Disorder;    Paramagnetic-ferromagnetic transition;    Super-paramagnetic;   

DOI  :  10.1016/j.jallcom.2018.10.360

来源: Elsevier

【 摘 要 】

Solid solutions of new double perovskite oxides La2NixCo1-xMnO6 (x = 0.2, 0.25, 0.5, 0.75, 0.8) were synthesized by solid-state reaction method. The X-ray powder diffraction data show that all the compounds crystallize in the monoclinic structure with space group P21/n at room temperature. The elementary composition of the powders was determined by the electron Probe Microanalysis. Raman and IR spectra show strong bands at (520, 650 cm(-1)) and (426, 600 cm(-1)) respectively, attributed to the stretching vibration of Ni/Co-O and Mn-O bonds in the structure. The magnetic studies for all the compounds have been performed in both DC and AC magnetic fields in the temperature range from 2 to 300 K. All samples exhibit a main paramagnetic to ferromagnetic (PM-FM) transition between 232 K and 260 K, and their Curie temperature increases rapidly with increasing x values. Three samples with x = 0.2, 0.25 and 0.5 respectively display also a secondary PM-FM transition between 200 K and 208 K. The thermal variation of out of phase component of AC susceptibility presents also frequency-dependent transitions between 65 K and 110 K unfolding the existence of super-paramagnetic mono-domains in all samples. The band gap energy has been calculated and revealing semiconductor behavior for all samples. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

Free