Der Einfluß unmagnetischer Dotierungen auf die ESR-Linienbreite von antiferromagnetischen Verbindungen / The Influence of Non-Magnetic Dopants on the ESR Line Width of Antiferromagnetic Compounds

Abstract

ESR spectra of doped antiferromagnetic compounds exhibit a concentration-dependent line width ∆B̄(x). We have investigated polycrystalline samples of Cr2O3 doped with Ga2O3 and Al2O3. For temperatures T sufficiently high above the Néel point TN and for concentrations x≦10%, the experimental values of AB show a linear dependence on x. This behaviour deviates from theoretical predictions based on the method of second moments. Starting with other reasonable assumptions, we have developed a statistical model of resonance that describes ∆B(x) as a linear function of x. Moreover this allows us to deduce that as far as antiferromagnetic Cr2O3 is concerned, the dopants Ga2O3 and AI2O3 are distributed homogene­ously throughout the lattice sites.