Influence of magnetic anisotropy on hysteresis behavior in the two-spin model of a ferro/antiferromagnet bilayer with exchange bias

The influence of magnetic anisotropy of a ferromagnetic film on the phenomenon of exchange bias is studied here. Hysteresis behavior in the two-spin model of a ferro/antiferromagnetic (FM/AFM) bilayer with exchange bias has been investigated in detail. In this model a half-space of an AFM with fixed magnetic configuration comes in contact with a two-layer FM film. Twelve different types of magnetization curves M(H) (both with and without hysteresis) have been found. Some of the M(H) curves demonstrate unusual features, such as plateaus and inclined segments. The hysteresis loop becomes asymmetric if surface anisotropy is taken into account

Mass spectrometry measurements of the lower atmosphere of Venus

Mass spectrometer experiments installed on the descent vehicles of the Venera-11 and the Venera-12 are described. Data on the chemical composition of the lower atmosphere of Venus is discussed with emphasis on the isotope state of the basic components (carbon, oxygen, nitrogen) and of the inert gases

Field dependences of the magnetization and exchange bias in ferro/antiferromagnetic systems. II. Continuum model of a ferromagnetic layer

A model giving a qualitative explanation of the results of an experimental investigation of the field dependences of the magnetization in ferro- and antiferromagnetic media in contact with one another is proposed. In this model a thin ferromagnetic (FM) film with strong easy-plane anisotropy is described in the continuum approximation. It is shown that collinear and canted structures of the ferromagnetic layer can co-exist in the system studied. The ranges of the parameters (exchange interactions in the FM layer and through the FM/AFM interface, thickness of the FM layer, and magnitude of the external magnetic field) where a nonuniform state of the FM exists are found and explicit analytic expressions are obtained for the distribution of the magnetization in this state. The dependences of the total magnetization of the system on the magnitude of the external field are constructed in the physically important cases of "thin" and "thick" FM layers, and it is demonstrated that the experimentally observed unsymmetric dependence M (H) is possible. The results of the present work are compared with our previous results obtained using simpler model of a two-layer FM subsystem

Magnetization field-dependences and the "exchange bias" in ferro/antiferromagnetic systems. I. Model of a bilayer ferromagnetic

A qualitative model explanation of the experimentally obtained field dependences of the magnetization in ferro- and antiferromagnetic media in contact with one another is proposed. In this model a thin ferromagnetic (FM) film on an antiferromagnetic (AFM) substrate consists of only two ferromagnetic layers. This is the simplest model which admits a spatially nonuniform FM state. In this exactly solvable model it shown that a range of fields exists where a stable collinear (canted) structure of the FM subsystem obtains. This structure corresponds to inclined sections of the field dependence M (H) of the magnetization which are not associated with the kinetics of the magnetization reversal process. In the model proposed, for systems with large easy-plane anisotropy the magnetization reversal process with "exchange bias" taken into account is strictly symmetric as a function of the field provided that the additional weak FM anisotropy in the easy plane is neglected. When this anisotropy in the easy plane is taken into account hysteresis appears in the magnetization curve and the field dependence M (H) becomes asymmetric