Reversible exchange bias in epitaxial V2O3/Ni hybrid magnetic heterostructures.

In this work we present a temperature and angular dependent study of the structural and magnetic properties in highly crystalline V2O3/Ni/Zr magnetic heterostructure films. Our investigation focuses on the coupling between the ferromagnetic Ni layer and V2O3layer which undergoes an antiferromagnetic/paramagnetic phase transition coupled to the structural phase transition of the material at around 150 K. Structural investigations using x-ray diffraction reveal highly crystalline films of a quality which has previously not been reported in the literature. The Ni layers display an absence of in-plane magnetic anisotropy owing to the highly textured (1 1 1) layering of the Ni films on the underlying V2O3(0 0 0 1) oriented layer. During the transition we observe a strain related enhancement of the coercivity and the onset of a weak exchange bias for cooling under an external magnetic field. Heating the films to above the transition temperature, the exchange bias in the Ni is removed and can be reversed upon subsequent cooling under an inverted external magnetic field. Using temperature dependent polarized neutron reflectometry we investigate the film structure at the interface, capturing the magnetic and nuclear profiles.

[Cerebral circulatory disorders while taking contraceptives]. / Narusheniia mozgovogo krovoobrashcheniia pri upotreblenii kontratseptivnykh sredstv.

Two observations of cerebral circulation disturbances developed by young women who used contraceptives are described. In one of them thrombosis of the median cerebral artery was diagnosed angiographically. In the other woman thromboses of the dural veins were revealed on autopsy. The pathogenesis of the arterial and venous cerebral circulation disturbances in women using contraceptives is discussed. The role of some additional risk factors, such as, obesity and smoking, is stressed.

PIP: Observations of cerebral circulation disturbances developed in young women who had used contraceptives are observed. In 1 of them, thrombosis of the medium cerebral artery was diagnosed angiographically. In the other woman, thromboses of the dural veins was revealed on autopsy. The pathogenesis of the arterial and venous cerebral circulation disturbances in women using contraceptives is discussed. The role of some additional risk factors, such as obesity and smoking, is stressed. (author's modified)