Magnetic properties of lightly doped antiferromagnetic YBa2Cu3Oy

Magnetic properties of spin-orbital polarons in lightly doped cobaltates.

We present a numerical treatment of a spin-orbital-polaron model for NaxCoO2 at small hole concentration (0.7 < x 1). We demonstrate how the polarons account for the peculiar magnetic properties of this layered compound: They explain the large susceptibility; their internal degrees of freedom lead both to a negative Curie-Weiss temperature and yet to a ferromagnetic intralayer interaction, ther...

Magnetic order in lightly doped La2-xSrxCuO4.

We study long wavelength magnetic excitations in lightly doped La2-xSrxCuO4 (x</=0.03) detwinned crystals. The lowest energy magnetic anisotropy induced gap can be understood in terms of the antisymmetric spin interaction inside the antiferromagnetic (AF) phase. The second magnetic resonance, analyzed in terms of in-plane spin anisotropy, shows unconventional behavior within the AF state; it le...

Spin correlations and magnetic susceptibilities of lightly doped antiferromagnets

We calculate the spin correlation function and the magnetic longitudinal and transverse susceptibilities of a two-dimensional antiferromagnet doped with a small concentration of holes, in the t-J model. We find that the motion of holes generates spin fluctuations which add to the quantum fluctuations, the spin correlations decaying with the inverse of the spin distance, while increasing with do...

Local magnetic properties of antiferromagnetic FeBr2.

Freezing of stripes in lightly-doped La2−xSrxCuO4 as manifested in magnetic and transport properties of untwinned single crystals

Resistivity and magnetization measurements are used for studying the transverse sliding of AF domain boundaries in lightly doped La2−xSrxCuO4. We discuss that it is the freezing of the transverse boundary motion that is responsible for the appearance of “spin-glass” features at low temperatures.