Effect of Y-doping on the magnetic and charge orderings in Nd_2/3Ca_1/3MnO₃

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• 作者：Elena Fertman ; Anatoly Beznosov ; Denis Sheptyakov ; Vladimir Desnenko ; Marcela Kajnakova ; Alex ; er Feher ; Dmitry Khalyavin
• 关键词：Magnetic structure ; Neutron diffraction ; Phase transformation ; Charge ordering
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2009
• 出版时间：February 2009
• 年：2009
• 卷：321
• 期：4
• 页码：316-320
• 全文大小：300 K

文摘

The shifts of the magnetic and charge ordering transition temperatures caused by Nd substitution for Y in Nd_2/3Ca_1/3MnO₃ CMR narrow-band perovskite manganite have been studied. At low temperatures, three different long-range magnetic orderings consistent with a phase separation scenario have been observed in the doped compound (Nd_0.9Y_0.1)_2/3Ca_1/3MnO₃ by neutron-diffraction study: the antiferromagnetic orderings of PCE and DE types existing below 110 and 60 K, respectively, and the ferromagnetic one of B type existing below 42. Magnetic phase transformations temperatures as well as those of charge ordering have been found to be structural-dependent. Y-doping leads to the decrease of the anisotropy of the orthorhombic Pnma crystal lattice b/√2c, which causes a decrease of the indirect exchange parameters in the system and thus a decrease in the magnetic transformation temperatures for 20–30 K in the doped compound. Doping leads as well to the higher level of the coherent Jahn–Teller distortions of the MnO₆ octahedra in the 200–300 K temperature region, which results in the increase of the charge ordering temperature for 80 K.