1 / 22

Asymmetry in Standar d model: Experimentally obtained:

Asymmetry in Standar d model: Experimentally obtained:. Ferroelectric. Ferromagnetic. Ferrotoroidic. Ferroelastic. V ýzkum a praktické využití magnetických feroelektrik S tanislav Kamba Fyzikální ústav AVČR, Na Slovance 2, 182 21 Praha 8 kamba @fzu.cz.

nan
Download Presentation

Asymmetry in Standar d model: Experimentally obtained:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Asymmetry in Standard model: Experimentally obtained:

  2. Ferroelectric Ferromagnetic Ferrotoroidic Ferroelastic Výzkum a praktické využití magnetických feroelektrikStanislav KambaFyzikální ústav AVČR, Na Slovance 2, 182 21 Praha 8kamba@fzu.cz Multiferoika jsou materiály, ve kterých koexistují dvě a více feroických vlastností.

  3. Sketch of MERAM element Bibes & Barthélémy,Nature Materials, 7, 425(2008) Chen et al. APL 89, 202508 (2006)

  4. Tunnel junctions with multiferroic barriers M || M M || M La0.1Bi0.9MnO3 magnetoferroelectrics, 2 nm thin film M. Gajek et al.Nature Materials, 6, 296 (2007)

  5. Classification of insulating oxides Béaet al.JPCM 20, 434221(2008) Fiebig, J. Phys. D: Appl. Phys. 38, R123 (2005)

  6. Multiferroics with spiral magnetic structure Kimura et al. Nature 426, 55 (2003) TbMnO3, TN=40 K, TC=27 K T. KimuraAnnu. Rev. Mater. Res.37, 387 (2007)

  7. Different types of multiferroics • Type-II: Magnetically driven multiferroics, TC< TN • Multiferroics with spiral magnetic structure • The inverse Dzyaloshinskii-Moriya mechanism •  - constant proportional to the spin orbit coupling and superexchange interaction • eij – unit vector connecting the neighboring i and j sites • b) Multiferroics with collinear magnetic structure Symmetric (Si.Sj)-type interaction, termed (super)exchange striction T. KimuraAnnu. Rev. Mater. Res.37, 387 (2007) H. Kimura et al.J. Phys. Soc. Jpn. 75, 113701 (2006)

  8. Strain induced ferroelectricity and ferromagnetism in tensile strained EuTiO3/DyScO3 Lee et al. Nature 466, 954 (2010) FZÚ AVČR; kamba@fzu.cz

  9. Strain-induced ferroelectric phase transition in EuTiO3/DyScO3 +1% tensile strain PS  30 C/cm2 Nature 476, 114 (2011) Lee et al. Nature 466, 954 (2010)

  10. Strain induced ferromagnetism in tensile strained EuTiO3/DyScO3 Lee et al. Nature 466, 954 (2010)

  11. Magnetic dependence of TO1 phonon frequency EuTiO3/ LSAT Kamba et al. PRB 85, 094435 (2012)

  12. Comples THz spectra of YMnO3 single crystal Kadlec et al. PRB 84, 174120 (2011)

  13. Predictions for the EDM magnitude of electrone

  14. - + switch s with H or + switch d with E - Electron with an electric dipole moment • Material property requirements: • Ferroelectric, switchable at few K, large polarization • Magnetic, but not ordered at a few K • Macroscopic sample (around 1 cm) • A low temperature multiferroic! d = a s; switching the electric dipole moment switches the spin moment K.Z. Rushchanskii et al., Nature Materials, 9, 649(2010)

  15. EuTiO3 TN=7 K paraelectric a=3.9 Å BaTiO3 ferroelectric a=4.0 Å (Eu,Ba)TiO3

  16. Dielectric and magnetic properties of Eu0.5Ba0.5TiO3 Orthorhombic Amm2 Cubic Pm3m TN=1.9 K TC=215 K T Rushchankii et al., Nature Materials, 9, 649 (2010) V. Goian et al. JPCM23, 025904(2011) S. Kamba, Čs. čas. fyz. 60, 329 (2010)

  17. Při frekvencích< 10 THz optické zdroje září málo Při frekvencích>10GHz klesá účinnost obvodů: elektrony nestačí sledovat rychlé změny elmg. pole Elekromagnetické spektrum „THz mezera” OPTIKA ELEKTRONIKA nízké frekvence radiové vlny mikro- vlny viditelné rtg. záření gamma frekvence [Hz] • 100 103 106 109 1012 1015 1018 1021 1024 kilo mega giga tera peta exa zetta yotta Infrač. UV vlnová délka 1000km 1km 1m 1mm 1μm 1nm 1pm 1fm „tradiční“ zdroje – příliš slabé: FZÚ AVČR; kamba@fzu.cz

  18. I.3. Dielectric spectrum A set of the frequency -temperature dependences should be studied Dielectric spectrum – a sum of the dielectric dispersion regions FZÚ AVČR; kamba@fzu.cz

  19. THz laboratoř FZÚ AVČR; kamba@fzu.cz

  20. Magnetický kryostat v THz laboratoři FZÚ AVČR; kamba@fzu.cz

  21. Infračervená laboratoř FZÚ AVČR; kamba@fzu.cz

More Related