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Magnetic polaron and Fermi surface effects on the ESR spin-flip scattering of above

✍ Scribed by R.R. Urbano; P.G. Pagliuso; C. Rettori; S.B. Oseroff; J.L. Sarrao; P. Schlottmann; Z. Fisk


Publisher
Elsevier Science
Year
2004
Tongue
English
Weight
427 KB
Volume
354
Category
Article
ISSN
0921-4526

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✦ Synopsis


The spin-flip scattering (SFS) between conduction and Eu 2þ 4f 7 ( 8 S 7=2 ) electrons in the paramagnetic phase of EuB 6 (TXT C % 15 K) is studied by electron spin resonance (ESR) and magneto-resistance (MR) experiments. The observed Dysonian resonance suggests a metallic environment for the Eu 2þ ions. ESR at high field, H ffi 12:05 kG (n ffi 33:9 GHz), shows an anisotropic line width with cubic symmetry. ESR at low-field, 1.46 kG (4.1 GHz) and 3.35 kG (9.5 GHz), shows broader line width and smaller anisotropy than at higher field. The narrowing and anisotropy of the line width at high fields are indicative of a homogeneous resonance where the line width is mainly governed by the SFS mechanism due to the exchange interaction between Eu 2þ 4f 7 and conduction electrons. Besides the negative MR, we found an anisotropic MR with cubic symmetry. These results are interpreted in terms of magnetic polaron and Fermi surface effects.