Defect of Structure, Magnetic and Transport Properties of Ceramic of Manganite-Lanthanum Perovskites La1-xMex2+MnO3± (Me2+ = Ca2+ (sic)Sr2+)

被引:0
作者
Turchenko, V. A. [1 ]
Pashchenko, V. P. [1 ]
Prokopenko, V. K. [1 ]
Shemyakov, A. A. [1 ]
Pevenko, Yu F. [1 ]
Pashchenko, A. V. [1 ]
Sycheva, V. Ya [1 ]
机构
[1] NAS, Donetsk Phys Tech Inst, Donetsk, Ukraine
来源
METALLOFIZIKA I NOVEISHIE TEKHNOLOGII | 2008年 / 30卷
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摘要
The investigation of ceramic magnetoresistive manganite-lanthanum perovskites La1-xMex2+MnO3 +/-delta, (Me2+ = Ca2+ (sic) Sr2+; x = 0-0,3) was performed by x-ray, magnetic, NMR Mn-55 and resistance methods. It was found the increase of concentration Me2+ ions brings to decrease of rhombohedric distortion and volume of crystal lattice and specific resistance of ceramic. The differences of phase transition temperatures 'conduction-semiconduction' and 'ferromagnetic-paramagnetic' and an activation energy of lanthanum-calcium and lanthanum-strontium manganites have explained by their difference of defect structure. It was shown the conditions of electro-neutrality perform not only through transition Mn3+-> Mn4+ but also formation of anion vacancies. A magnetic phase diagrams describe the influence of composition to ferro, antiferro- and paramagnetic rectangular components. The broad asymmetric Mn-55 NMR spectrum confirms the existence of a high-frequency electron-hole exchange between Mn3+<-> Mn4+ and heterogeneity of their surroundings by other ions and vacancies.
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页码:105 / 116
页数:12
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