Role of Ge in Bridging Ferromagnetism in the Giant Magnetocaloric Gd5(Ge1−xSix)4 Alloys

作     者：D. Haskel Y. B. Lee B. N. Harmon Z. Islam J. C. Lang G. Srajer Ya. Mudryk K. A. Gschneidner, Jr. V. K. Pecharsky 

作者机构：Advanced Photon Source Argonne National Laboratory Argonne Illinois 60439 USA Condensed Matter Physics Program Ames Laboratory Iowa State University Ames Iowa 50011-3020 USA Ames Laboratory and Department of Materials Science and Engineering Iowa State University Ames Iowa 50011-3020 USA 

出 版 物：《Physical Review Letters》 (Phys Rev Lett)

年 卷 期：2007年第98卷第24期

页      面：247205-247205页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

主　　题：Gadolinium alloys 

摘      要：X-ray magnetic circular dichroism (XMCD) measurements and density functional theory (DFT) are used to study the electronic conduction states in Gd5(Ge1−xSix)4 materials through the first-order bond-breaking magnetostructural transition responsible for their giant magnetocaloric effect. Spin-dependent hybridization between Ge 4p and Gd 5d conduction states, which XMCD senses through the induced magnetic polarization in Ge ions, enables long-range Ruderman-Kittel-Kasuya-Yosida ferromagnetic interactions between Gd 4f moments in adjacent Gd slabs connected by Ge(Si) bonds. These interactions are strong below but weaken above the Ge(Si) bond-breaking transition that destroys 3D ferromagnetic order.