Der Einfluß der Spin-Kopplung auf die ESR-Spektren der Orthochromite YCrO3 und LuCrO3 / The Influence of Spin-coupling on the ESR-spectra of the Orthochromites YCrO3 and LuCrO3

Abstract

Abstract Polycrystalline samples of stoichiometric YCrO3 and LuCrO3 were investigated by ESR in the temperature range between 140 K and 520 K. Although the orthochromites have a complicated spin structure, the line width shows the temperature dependence of simple antiferromagnetic systems. Up to a high degree the spectra have a Lorentzian line shape. The ESR intensity confirms the predictions of a cluster model. The coupling energy describing the gap between the bounded and the resonance state was found to be ⊿E = 250 cm-1 for YCrO3 and ⊿E = 210 cm-1 for LuCrO3 . There is a distinct relation between the excitation energy ⊿E and the volume V of the elementary cell. Further calculations concerning the isotropic exchange interaction result in a coupling constant of J = 5.55 cm-1 for YCrO3 and J = 4.67 cm-1 for LuCrO3.