Pulsed EPR spectroscopy of Gd3+ centers in Ca1-xRxF2+x (R=La, Y) mixed crystals

被引：4

作者：

Arauzo, AB

Alcala, R

Alonso, PJ

机构：

[1] Institute de Ciencia de Materiales de Aragón, Universidad de Zaragoza, Zaragoza

[2] Institute de Ciencia de Materiales de Aragón, 50009 Zaragoza, Pza. S. Francisco s/n.

来源：

APPLIED MAGNETIC RESONANCE | 1997年 / 12卷 / 2-3期

关键词：

ALKALINE-EARTH FLUORIDES; DEFECT STRUCTURE; SOLID-SOLUTIONS; GD-3+; PROBES;

D O I：

10.1007/BF03162203

中图分类号：

O64 [物理化学（理论化学）、化学物理学]; O56 [分子物理学、原子物理学];

学科分类号：

070203 ; 070304 ; 081704 ; 1406 ;

摘要：

A study of Gd3+ centers in Ca1-xRxF2+x (R = La, Y) crystals using pulsed EPR spectroscopy is presented. The echo-induced EPR (ESE-EPR) spectrum shows, besides the signal of slightly perturbed cubic Gd3+ centers, a broad signal at g approximate to 2 due to Gd3+ centers at low symmetry sites. To describe the effects of R3+ ions on the EPR Gd3+, a model, including cubic and linear R3+-2F(i)(-) centers, is developed. Its predictions are compared with the experimental results. The composition dependence of the EPR signal due to slightly perturbed cubic Gd3+ centers in mixed Ca1-xRxF2+x crystals is explained taking into account the different clustering tendency in La and Y crystals. Moreover, the formation of mixed clusters involving R3+ and Gd3+ ions is proposed for both series of samples. A greater clustering trend is found in the Y crystals than in the La ones. Gd3+ ions are found to be a ''non innocent'' paramagnetic probe for structural studies in these mixed crystals.

引用

页码：375 / 387

页数：13

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