Simultaneous Pressure-Induced Magnetic and Valence Transitions in Type-I Clathrate Eu8Ga16Ge30

Autor(es):Mostrar menos -

Onimaru, Takahiro ^[1] ; Tsutsui, Satoshi ^[2] ; Mizumaki, Masaichiro ^[2] ; Kawamura, Naomi ^[2] ; Ishimatsu, Naoki ^[3] ; Avila, Marcos A. ^{[4, 1]} ; Yamamoto, Shuhei ^[1] ; Yamane, Haruki ^[1] ; Suekuni, Koichiro ^[1] ; Umeo, Kazunori ^[5] ; Kume, Tetsuji ^[6] ; Nakano, Satoshi ^[7] ; Takabatake, Toshiro ^{[1, 8]}

Afiliação do(s) autor(es)

^[1] Hiroshima Univ, Grad Sch Adv Sci Matter, Dept Quantum Matter, Hiroshima 7398530 - Japan

^[2] Japan Synchrotron Radiat Res Inst, SPring 8, Sayo, Hyogo 6795198 - Japan

^[3] Hiroshima Univ, Grad Sch Sci, Dept Phys Sci, Hiroshima 7398526 - Japan

^[4] Univ Fed ABC, CCNH, BR-09210580 Santo Andre, SP - Brazil

^[5] Hiroshima Univ, Cryogen & Instrumental Anal Div, N BARD, Hiroshima 7398526 - Japan

^[6] Gifu Univ, Dept Mat Sci & Technol, Gifu 5011193 - Japan

^[7] Natl Inst Mat Sci, Tsukuba, Ibaraki 3050044 - Japan

^[8] Hiroshima Univ, Inst Adv Mat Res, Hiroshima 7398530 - Japan

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN; v. 83, n. 1 JAN 2014.
• Citações Web of Science: 1

Resumo

We have performed X-ray magnetic circular dichroism (XMCD) and X-ray absorption spectroscopy (XAS) measurements at pressures up to 17 GPa for the clathrate Eu8Ga16Ge30 (Curie temperature T-C = 36 K). The temperature dependence of the XMCD spectra agrees well with that of the DC magnetization at ambient pressure. The TC is gradually enhanced with increasing pressures up to 13.3 GPa, and the divalent state of the Eu ions with J = 7/2 remains stable, but at 17 GPa the XMCD intensity is strongly suppressed and a spectral weight corresponding to the trivalent state of Eu ions (with no magnetic moment) appears in the XAS spectrum. The concurrent change from the type-I clathrate structure to an amorphous phase has been observed by X-ray diffraction experiment. We conclude that the amorphization of this compound induces the mixed valence state, which collapses the ferromagnetism. (AU)

• Processo FAPESP: 12/17562-9 - Preparação de monocristais orientados para estudos de anisotropias eletrônicas, magnéticas e térmicas
• Beneficiário: Marcos de Abreu Avila
• Modalidade de apoio: Auxílio à Pesquisa - Regular