Influence of Na Addition on Magnetic and Magnetocaloric Effects of Laub class="a-plus-plus">0.67ub>Pbub class="a-plus-plus">0.13ub>Naub class="a-plus-plus">0.2ub>MnOub class="a-plus-plus">3ub> Ceramics

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• 作者：Asma Zaidi ; Ahmed Dhahri ; J. Dhahri…
• 关键词：Na ; doped manganites ; Griffiths phase ; Magnetocaloric effect ; Electrical transport
• 刊名：Journal of Superconductivity Incorporating Novel Magnetism
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：29
• 期：10
• 页码：2543-2551
• 全文大小：790 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Superconductivity, Superfluidity and Quantum Fluids
  Magnetism and Magnetic Materials
  Condensed Matter
  Characterization and Evaluation Materials
  
• 出版者：Springer New York
• ISSN：1557-1947
• 卷排序：29

文摘

Structural, magnetic, magnetocaloric, and electrical properties are reported for mixed-valence manganite Laub>0.67ub>Pbub>0.13ub>Naub>0.2ub>MnOub>3ub>. X-ray diffraction reveals that the sample crystallizes in the rhombohedric structure with the R-3c space group. The magnetic properties of the polycrystalline Laub>0.67ub>Pbub>0.13ub>Naub>0.2ub>MnOub>3ub> compound are discussed in detail, based on the susceptibility, magnetization, and isotherm. The sample presents a ferromagnetic property with Tub>Cub>= 275 K and a Griffiths phase at Tub>Gub>= 325 K which gives the existence of ferromagnetic clusters in the paramagnetic domain. A large deviation is usually observed between field cooled (FC) and zero field cooled (ZFC). M(T) is a low temperature below the blocking temperature. At 40 K, a spin-glass or a cluster-glass state is seen to arise from a ferromagnetic state. This is caused by the competition between the antiferromagnetic and ferromagnetic interactions. The electrical properties show the presence of a metal–semiconductor transition at Tub>M−Scub>. To understand the dependence of disorder with the transport mechanism, we used the phenomenological equation for resistivity under a percolation approach, which is dependent on the phase segregation of a paramagnetic semiconductor and ferromagnetic metallic regions.