The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 03, 1990
Filed:
Jun. 23, 1989
Hiroshi Bando, Tsukuba, JP;
Akira Sakai, Kawasaki, JP;
Director General of Agency of Industrial Science and Technology, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A scanning tunneling microscope according to the present invention comprises a tip for emitting spin-polarized electrons and a magnet for applying a magnetic field to this tip. This tip is constituted of a metal needle made of a tungsten and an EuS layer about 400 .ANG. which is coated on the surface of the metal needle. This tip is brought to such a close distance to the surface of the specimen that tunnel current flows. A magnetic field is applied to the axial direction of the tip a bias voltage is applied between the tip and the specimen and the tip is made to scan the surface of the specimen. The tip having a magnetic field applied to the axial direction thereof emits only spin-polarized electrons with the electron spins oriented in the axial direction. The spin-polarized electrons flows only in the area at the surface of the specimen where empty states for the electrons having spins in the parallel direction are distributed. By detecting the flow of the electrons, that is, the tunnel current, it is possible to obtain the distribution of the electrons having downward or downward spins. The shape of the pointed end of the tip is almost the same as that of a tip used in an ordinary STM. This makes it possible to measure the distribution of the electron spins with an atomic scale resolution.