Temperature Variation and Separation Dependence of Exchange Interactions ofGd3+Pairs in LaCl3

Abstract

${\mathrm{Gd}}^{3+}$ pairs in La${\mathrm{Cl}}_3$ provide examples of comparable magnetic and exchange interactions for which precise values of the interaction constants can be found from microwave resonance fields. The separation dependence of the exchange is estimated from the observed temperature variation and found to be anomalous.