Magnetic and morphological characterization of Nd2Fe14B magnets with different quality grades at low temperature 5–300 K

Autor: Elisa Maria Ruiz-Navas, Cristian Cristache, Ignacio Valiente-Blanco, Juan-Antonio Martinez-Rojas, C. Bernini, Carlo Ferdeghini, Jose-Luis Perez-Diaz, Efren Diez-Jimenez, Juan Sanchez-Garcia-Casarrubios, Fabio Canepa
Přispěvatelé: European Commission
Rok vydání: 2018
Předmět:
Zdroj: e-Archivo. Repositorio Institucional de la Universidad Carlos III de Madrid
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ISSN: 0304-8853
DOI: 10.1016/j.jmmm.2017.11.109
Popis: An increasing number of cryogenic devices may benefit from the use of Nd2Fe14B permanent magnets. However, it is necessary to precisely know their behavior because magnetization varies significantly due to Spin Reorientation Transition. In this work, magnetic and morphological characterization of Nd2Fe14B commercial polycrystalline magnets with different quality grades from 5 to 300 K is provided. A set of magnets ranging from N35 to N52 quality have been analyzed. Mean grain dimension as well as material composition elements are provided. Higher quality magnets show smaller mean grain dimensions. Regarding cryogenic temperatures, the well know spin transition effect appears in all the magnets as expected, however, the transition temperature occurs at different temperatures in a range from 112 to 120 K which is lower than those obtained for single crystal samples. Moreover, the relative variation of the remanence from 300 to 5 K is lower than 4% while the maximum expected variation is in average 11%. As extra information, the same analyzes are provided for additional quality grades N40M, N40S, N40SH and N40UH. The research leading to these results has received funding from the European Community's Seventh Framework Programme ([FP7/2007-2013]) under grant agreement n° 263014.
Databáze: OpenAIRE
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