Random competing interactions in perovskites

E.E. VOGEL , P. VARGAS, J. CARTES, G. ALEJANDRO, L. STEREN

Rep. Checa

Conferencia; Annual Conference of the European Society of Condensed Matter; 2004

European Society of Condensed Matter

Magnetic measurements, such as magnetic hysteresis, have been performed for per-ovskites randomly doped with Ce atoms. Loops show partially reproducible hysteresis cycles. At very weak fields (under 50 Oe) a step-like behavior is found with jumps in the magnetization at certain values of the external magnetic field. This is probably due to random competing interactions whose origin is discussed. An Ising Hamiltonian including a mixture of ferromagnetic and antiferromagnetic interactions on a simple cubic lattice is tried on showing that some of the features of the experimental cycles can be reproducerd by means of a Monte Carlo simulation. Temperature dependence is also mimicked and discussed. Further developments of this phenomenon are brought out.