Role of Ge in bridging ferromagnetism in the giant magnetocaloric Gd{sub 5}(Ge{sub 1-x}Si{sub x}){sub 4} alloys.
X-ray magnetic circular dichroism (XMCD) measurements and density functional theory (DFT) are used to study the electronic conduction states in Gd{sub 5}(Ge{sub 1-x}Si{sub x}){sub 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.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 915331
- Report Number(s):
- ANL/XSD/JA-57959
- Journal Information:
- Phys. Rev. Lett., Journal Name: Phys. Rev. Lett. Journal Issue: Jun. 15, 2007 Vol. 98; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- ENGLISH
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