Giant Planar Hall Effect In Ferromagnetic Semiconductors
Relative to ferromagnetic metals, ferromagnetic semiconductors: enable one to realize devices that have no analogs among ferromagnetic metal devices; offer better performance (e.g. enhanced magnetic switching); and are more compatible with existing semiconductor technologies, notably in regards to the level of control and spatial resolution associated with contemporary nanofabrication and epitaxial growth methods. This invention has the further advantage that the magnitude of the GPHE is generally size-independent down to the submicron scale. Thus, for applications involving nanostructures, the sensitivity of this invention is comparable to SQUID-based techniques. Accordingly, this technology is uniquely well suited to studies of the dynamics and magnetoresistance of individual magnetic domain walls in spintronic systems. PATENT APPLICATION: U.S. patent application 602,537, filed June 23, 2003.
Spintronic applications that might benefit from GPHE ferromagnetic semiconductor materials include: high-density, non-volatile information storage; enhanced magnetic microswitches; quantum computer microprocessors; and devices for facilitating spintronics development, especially for measurement of domain wall phenomena.
Researchers at the University of California and the California Institute of Technology have invented (Ga,Mn)As-based ferromagnetic semiconductor materials that exhibit the giant planar Hall effect (GPHE). In GPHE, the localized alignment of electron spins causes a change in resistance. With this invention, the GPHE-induced resistance change in multiterminal, micron-scale structures can be as large as ~100 Ω, about four orders of magnitude higher than the analogous resistances previously observed in metallic ferromagnets. This invention has sufficient resolution to allow real-time observations of the nucleation and field-induced propagation of individual magnetic domain walls, which is of prime importance for future spintronics development. Such a pronounced GPHE also has important implications for the improvement of magnetic switching and other spintronic functions.
Patent Number: US6879012B2
Application Number: US2003602537A
Inventor: Tang, Hongxing | Roukes, Michael L. | Kawakami, Roland K. | Awschalom, David D.
Priority Date: 21 Jun 2002
Priority Number: US6879012B2
Application Date: 23 Jun 2003
Publication Date: 12 Apr 2005
IPC Current: G01R003307 | H01L002982 | H01L004306
US Class: 257421 | 257048 | 257425 | 257427 | 257609 | 257615 | 257E43003
Assignee Applicant: The Regents of the University of California | California Institute of Technology,Pasadena
Title: Giant planar hall effect in epitaxial ferromagnetic semiconductor devices
Usefulness: Giant planar hall effect in epitaxial ferromagnetic semiconductor devices
Summary: For read head sensors used in hard disk drives and other magnetic storage devices.
Novelty: Pressure sensor for hard disk drive, utilizes ferromagnetic semiconductor Hall bar gage structure that produces pressure sensing signals in response to deflection of membrane
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6879012
Tech ID/UC Case 10280/2004-034-0 Related Cases 2004-034-0
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