device and method for the production of schaltbarem temporary magnetism in oxide materials by electric fields

摘要

The invention relates to a method and to an apparatus for producing switchable temporary magnetism in oxidic materials by means of electrical fields, wherein on two opposing surfaces (11, 12) of the oxidic material (1, 2, 3) at least one electrode (21, 22) each is attached, wherein upon applying an electrical potential difference the oxidic material (1, 2, 3) is superimposed with the electrical field (E) and thereby an oxide material arrangement (13) is present, wherein oxygen vacancies, which are already present in the oxidic material (1, 2, 3), are redistributed in the oxidic material (1, 2, 3) when applying the electrical field (E), and thus a gradient of the oxygen concentration develops, wherein in the cathode region (14) of the oxidic material (1, 2, 3) an oxygen vacancy zone (4) is created, which results in a valence change of the cations such that magnetic moments can be produced. The object is to temporarily produce, at room temperature, magnetism in an oxidic material by way of an electrical field (E), which leads to macroscopic applications and functional elements. The solution is that at least one device (15, 20) for detecting the magnetism that forms in the oxygen vacancy zone (4) due to the applied electrical field (E) and that can be registered is arranged directly outside the cathode region (14) of the oxidic material (1, 2, 3), wherein in the oxygen vacancy zone (4) the valence of the cations of the oxidic material (1, 2, 3) decreases if the oxygen vacancy concentration increases, and increases if the oxygen vacancy concentration decreases, wherein a reduction in the valence of the cations in the oxidic material (1, 2, 3) produces magnetic moments (19), which may be present either in a disorganized manner, thereby rendering the oxidic material (1, 2, 3) paramagnetic, or which couple with each other, thereby rendering the oxidic material (1, 2, 3) either ferromagnetic, ferrimagnetic, or antiferromagnetic, and wherein by switching the electrical field (E) the respective magnetism in the oxide material arrangement (13) can be reversibly switched and the original state can be restored without magnetic moments.