MANIFESTATION OF FERROMAGNETISM IN LIGHTLY OXYGEN-DOPED LA2CUO4 SINGLE-CRYSTALS IN MAGNETIC-FIELDS H-LESS-THAN-50 OE

The temperature and field dependences chi(T,H) in La2CuO4+delta single crystals with delta<0.015 have been investigated in magnetic fields 0 .1<H<450 Oe by the differential magnetic susceptibility method. It was found that under oxygen doping conditions ferromagnetic regions are f ormed. These regions produce a characteristic curve of the magnetic su sceptibility chi(T,H), which is observed only in magnetic fields of le ss than 50 Oe. This can be explained by the formation of ferrons [A. A harony ct al. Phys. Rev. Lett. 60, 1330 (1988); L. I. Glazman and A. S . Ioselevich, Z. Phys. B 80, 268 (1990)] in an antiferromagnetic matri x. (C) 1996 American Institute of Physics.