Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Thermal-magnetic-electric oscillator based on spin-valve effect
Department of Physics, University of Gothenburg.
KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
Department of Physics, University of Gothenburg.
Department of Physics, University of Gothenburg.
Show others and affiliations
2012 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, 044315- p.Article in journal (Refereed) Published
Abstract [en]

A thermal-magnetic-electric valve with the free layer of exchange-spring type and inverse magnetoresistance is investigated. The structure has S-shaped current-voltage characteristics and can exhibit spontaneous oscillations when integrated with a conventional capacitor within a resonator circuit. The frequency of the oscillations can be controlled from essentially dc to the GHz range by the circuit capacitance.

Place, publisher, year, edition, pages
2012. Vol. 111, 044315- p.
National Category
Condensed Matter Physics
Identifiers
URN: urn:nbn:se:kth:diva-91298DOI: 10.1063/1.3686735ISI: 000300948600093Scopus ID: 2-s2.0-84863238065OAI: oai:DiVA.org:kth-91298DiVA: diva2:509282
Note
QC 20120313Available from: 2012-03-12 Created: 2012-03-12 Last updated: 2017-12-07Bibliographically approved
In thesis
1. Spin-diode effect and thermally controlled switching in magnetic spin-valves
Open this publication in new window or tab >>Spin-diode effect and thermally controlled switching in magnetic spin-valves
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis demonstrates two new device concepts that are based on the tunneling and giant magnetoresistance effects. The first is a semiconductor-free asymmetric magnetic double tunnel junction that is shown to work as a diode, while at the same time exhibiting a record high magnetoresistance. It is experimentally verified that a diode effect, with a rectification ratio of at least 100, can be obtained in this type of system, and that a negative magnetoresistance of nearly 4000% can be measured at low temperature. The large magnetoresistance is attributed to spin resonant tunneling, where the parallel and antiparallel orientation of the magnetic moments shifts the energy levels in the middle electrode, thereby changing their alignment with the conduction band in the outer electrodes. This resonant tunneling can be useful when scaling down magnetic random access memory; eliminating the need to use external diodes or transistors in series with each bit.

The second device concept is a thermally controlled spin-switch; a novel way to control the free-layer switching and magnetoresistance in spin-valves. By exchange coupling two ferromagnetic films through a weakly ferromagnetic Ni-Cu alloy, the coupling is controlled by changes in temperature. At room temperature, the alloy is weakly ferromagnetic and the two films are exchange coupled through the alloy. At a temperature higher than the Curie point, the alloy is paramagnetic and the two strongly ferromagnetic films decouple. Using this technique, the read out signal from a giant magnetoresistance element is controlled using both external heating and internal Joule heating. No degradation of device performance upon thermal cycling is observed. The change in temperature for a full free-layer reversal is shown to be 35 degrees Celsius for the present Ni-Cu alloy. It is predicted that this type of switching theoretically can lead to high frequency oscillations in current, voltage, and temperature, where the frequency is controlled by an external inductor or capacitor. This can prove to be useful for applications such as voltage controlled oscillators in, for example, frequency synthesizers and function generators. Several ways to optimize the thermally controlled spin switch are discussed and conceptually demonstrated with experiments.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. 85 p.
Series
Trita-FYS, ISSN 0280-316X ; 2012:11
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-91300 (URN)978-91-7501-287-2 (ISBN)
Public defence
2012-03-30, FB52, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Supervisors
Note
QC 20120313Available from: 2012-03-13 Created: 2012-03-12 Last updated: 2012-03-13Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopushttp://jap.aip.org/resource/1/japiau/v111/i4/p044315_s1

Authority records BETA

Korenivski, Vladislav

Search in DiVA

By author/editor
Andersson, SebastianKorenivski, Vladislav
By organisation
Nanostructure Physics
In the same journal
Journal of Applied Physics
Condensed Matter Physics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 56 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf