ELECTRON-SPIN-RESONANCE LINEWIDTH VARIATION WITH TEMPERATURE IN SOME RARE-EARTH SALTS - T1/T2 RATIONS

We have measured the temperature dependence of the electron-spin-resonance linewidth of Ce, Nd, and Sm in lanthanum magnesium nitrate from below 4°K to as high as 26°K. Both Ce and Nd displayed a linewidth which was essentially Lorentzian at the lowest temperature and which broadened with increasing temperature in accordance with an Orbach relaxation mechanism. A comparison of the strength of this broadening with standard relaxation measurements below 4°K indicated that T1T2 was 8.6 for the Nd sample and was estimated to be 13 for the Ce crystal. Sm displayed a temperature-dependent broadening which could be interpreted as due either to a Raman or an Orbach mechanism. © 1969 The American Physical Society.