Applied Physics a-Materials Science & Processing
The evolutions of electronic phase separation in manganites La(0.225)Pr(0.4)Ca(0.375)MnO(3) are studied by the specific temperature and magnetic-field cycling experiments. It is found that the electronic phase separation state at low temperature can be tuned substantially by temperature and/or magnetic-field cycles. Surprisingly, the initial more ferromagnetic metallic (FMM) nuclei can impede the growth of these nuclei during the cooling process. It implies that there must coexist more than two phases which take part in the complex first-order phase transitions, and the charge-disordered insulating phase is possible, one of the parent phases transiting into the FMM phase at low temperature. In addition, the accommodation strain is suggested to control the nucleation and growth of FMM domains.
关键词:
manganites
Journal of Applied Physics
The influence of epitaxial strain, tuned with tetragonal distortion c/a from 0.965 to 1.034 by choosing different substrates and varying film thickness, on the magnetic and transport properties of Nd0.45Sr0.55MnO3 thin films has been investigated. It is found that epitaxial strain, depending on the value of c/a, can enhance or decrease the stability of A-type AF to induce ferromagnetic fluctuation and C-type AF instead of A-type AF. (C) 2012 American Institute of Physics. [doi:10.1063/1.3671787]
关键词:
manganites
Avneesh Anshul
材料科学技术（英文）
Comprehensive investigation on the synthesis and electrical transport behaviors of polycrystalline samples of lanthanum manganite due to static disorder was reported. The process parameters were optimized for different batches to yield variable grain sizes. Different sintering conditions and technique like thermal cycling were employed to obtain better grain packing density. The liquid nitrogen and air quenching of the samples were carried out to restrict the grain growth with well defused grain boundary. Variable grain habits and sizes were synthesized by standard solid-state reaction and modified sol-gel synthesis routes. Large variation of grain size, connectivity and packing was observed by varying sintering temperature and synthesis technique. The process dependent grain sizes were observed in the wide range from 20 nm to 1.5μm by transmission and scanning electron microscopy. The variations in residual resistivity as well as metal-insulator transitions are observed. The observed data were analyzed on the basis of contributions from various dynamic interactions and static disorders.
关键词:
Order-disorder effect
Avneesh Anshul
材料科学技术（英文）
Comprehensive investigation on the synthesis and electrical transport behaviors of polycrystalline samples of lanthanum manganite due to static disorder was reported. The process parameters were optimized for different batches to yield variable grain sizes. Different sintering conditions and technique like thermal cycling were employed to obtain better grain packing density. The liquid nitrogen and air quenching of the samples were carried out to restrict the grain growth with well defused grain boundary. Variable grain habits and sizes were synthesized by standard solid-state reaction and modified sol-gel synthesis routes. Large variation of grain size, connectivity and packing was observed by varying sintering temperature and synthesis technique. The process dependent grain sizes were observed in the wide range from 20 nm to 1.5μm by transmission and scanning electron microscopy. The variations in residual resistivity as well as metal-insulator transitions are observed. The observed data were analyzed on the basis of contributions from various dynamic interactions and static disorders.
关键词:
Order-disorder effect
陈春霞
无机材料学报
电荷有序现象在混价过渡金属氧化物中早有研究, 钙钛矿锰氧化物中由于电荷有序与自旋有序、轨道有序、晶格畸变等相互关联而特别引人注目. 本文综述了有关电荷有序现象的早期
研究与近期进展, 重点介绍了电荷有序转变附近的一些物理异常现象与影响电荷有序态稳定的有关因素.
关键词:
锰氧化物
,
charge ordering
