Anmerkungen:
Die Gruppe "2-x", der Kleibuchstabe "x" sowie die Ziffer 4 im Titel sind tiefgestellt
Beschreibung:
We present a study of the magnetic susceptibility of La 2- x Sr x CoO 4 single crystals in a doping range0.3 ≤ x ≤ 0.8. Our data show a pronounced magnetic anisotropy for all compounds. This anisotropy is in agreement with a low-spin ground state ( S = 0) of Co 3+ for x ≥ 0.4 and a high-spin ground state ( S = 3/2) of Co 2+ . We compare our data with a crystal-field model calculation assuming local moments and find a good description of the magnetic behavior for x ≥ 0.5. This includes the pronounced kinks observed in the inverse magnetic susceptibility, which result from the anisotropy and low-energy excited states of Co 2+ and are not related to magnetic ordering or temperature-dependent spin-state transitions.