Temperature-Induced Changes in the EPR Spectrum of the Magnetic Center in Kaolin

✍ Scribed by Vladimir N. Vasyukov; Vladimir V. Shapovalov; Steven A. Schwarz; Miriam H. Rafailovich; Jonathan C. Sokolov; Vladimir A. Shapovalov; Viktor A. Beloshenko

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 135 KB
• Volume: 154
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.2001.2456

✦ Synopsis

Studies of kaolin have revealed an effect characterized by an unusual temperature-induced change of the EPR spectrum of the Fe3+ ion, which is the magnetic probe in kaolin-clay. At low temperature (T=4.2 K) a resonance line with an effective g-value g1=4.13 +/- 0.16 is observed. At high temperature (T=288 K) one observes a resonance line with the effective g-value g2=2.15 +/- 0.1. The transition from the low- to high-temperature spectrum is gradual and it is accompanied by a redistribution of the absorption intensity. The observed properties of the temperature dependence of the EPR spectrum are characteristic of systems with a multiminimum potential.