Magnetic hysteresis and refrigeration capacity of Ni—Mn—Ga alloys near Martensitic transformation     

傅斌  龙毅  段静芳  王超伦  常永勤  叶荣昌  吴光恒 《海洋学报(英文版)》2010,29(9)

This paper studies the magnetic hysteresis and refrigeration capacity of Ni--Mn--Ga alloys in detail during heating and cooling isothermal magnetisation processes. The Ni--Mn--Ga alloys show larger magnetic hysteresis when they transform from austenite to martensite, but smaller magnetic hysteresis when they transform from martensite to austenite. This behaviour is independent of either the pure Ni--Mn--Ga alloys or the alloys doped with other elements. Because of the existence of the magnetic hysteresis, the relation between the magnetic entropy change and refrigeration capacity is not simply linear. For practical consideration, magnetocaloric effect of Ni--Mn--Ga alloys should be investigated both on cooling and heating processes.  相似文献   

KKR-CPA-LDA计算方法对CuMnAl和CoMnAl以及CuCoMnAl合金的磁性研究          下载免费PDF全文

冯琳  朱志永  朱伟  刘恩克  唐晓丹  钱金凤  吴光恒  孟凡斌  刘何燕  罗鸿志  李养贤 《海洋学报》2010,32(9):6575-6579

采用KKR-CPA-LDA方法研究了CuMnAl,CoMnAl和CuCoMnAl四元合金中磁性原子磁矩和Co-Mn间的交换作用.通过与实验结果对比,揭示了Mn的磁矩和Co的磁矩以及它们的相互作用随成分变化的规律.研究发现,在Cu₅₀Mn_25+xAl25-x合金中超过化学配比并占据Al位的Mn原子是反铁磁的,而且由于近邻环境的不同,其磁矩大于原有Mn原子的磁矩.在Co₅₀Mn_{25+<  相似文献}   

纳米复合永磁材料中软磁性相交换硬化的研究          下载免费PDF全文

张帅  陈喜芳  阴津华  张宏伟  陈京兰  姜宏伟  吴光恒 《海洋学报》2010,32(9):6593-6598

本文就纳米复合永磁材料中软磁相被交换硬化问题,从一维模型和三维模拟计算进行了分析研究. 一维和三维各向异性样品研究表明,在相同微结构下,当硬磁相的各向异性降低时,除矫顽力降低外,在磁矩全部反转之前退磁曲线是一样的. 因此,硬磁相各向异性的降低不会导致最大磁能积(BH)_max增大和剩磁增加. 对于三维各向同性样品的模拟计算表明,降低硬磁相的各向异性会使剩磁和(BH)_max都明显降低. 因此,增强硬磁相的各向异性并增大硬磁相晶粒尺寸是提高  相似文献