Spin flopping in the quasi-twodimensional magnetic systems: application to YBa2Cu3O6+x

Abstract We have studied the role of antiferromagnetic anisotropy correlation coupling in the magnetic properties of low-dimensional systems. We used the quasi-two-dimensional Heisenberg model with anisotropic terms in the presence of a magnetic field. We found that if the applied magnetic field exceeds a certain value, the spin system becomes unstable and avoids this catastrophe by spin flopping to another spin configuration. This spin-flop transition is a direct consequence of the presence of the anisotropic antiferromagnetic correlations. This theory has been applied to YBa2Cu3O6+x.