Magnetic properties and magnetocaloric effect in NdxLa1-xFe11.5Al1.5 compounds

• 来源期刊: 中国物理B(英文版)
• 关键词: magnetic properties NaZn13-type compounds magnetic entropy change
• 年，卷（期）: 2008,（8）
• 页码范围: 3087-3092
• 页数: 6页
• 语种: 英文

摘要

Effects of Nd-doping on the magnetic properties and magnetocaloric effects (MCEs) of NdxLa1-xFe11.5Al1.5 have been investigated. Substitution of Nd leads to a weakening of the antiferromagnetic (AFM) coupling and an enhancement of the ferromagnetic (FM) coupling. This in turn results in a complex magnetic behaviour for Nd0.2La0.8Fe11.52Al1.5 characterized by the occurrence of two phase transitions at ～188 K (PM-AFM) and ～159 K (AFM-FM). As a result, a table-like MCE (9 J/kg·K) is found in a wide temperature range (160-185 K) for a field change of 0-5 T around the transition temperature, as evidenced by both the magnetic and calorimetric measurements. Based on the analysis of low-temperature heat capacity, it is found that the AFM-FM phase transition modifies the electron density significantly, and the major contribution to the entropy change comes from the electronic entropy change.