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Multiferroic
- 2. WHAT IS MULTIFERROICS ? • MULTIFERROICS HAVE BEEN FORMALLY DEFINED AS MATERIALS THAT EXHIBIT MORE THAN ONE PRIMARY FERROIC ORDER PARAMETER SIMULTANEOUSLY (I.E. IN A SINGLE PHASE).HOWEVER, THE DEFINITION OF MULTIFERROICS CAN BE EXPANDED TO INCLUDE NON-PRIMARY ORDER PARAMETERS, SUCH AS ANTIFERROMAGNETISM OR FERRIMAGNETISM. THE FOUR BASIC PRIMARY FERROIC ORDER PARAMETERS ARE • FERROMAGNETISM • FERROELECTRICITY • FERROELASTICITY • REF:HTTPS://EN.WIKIPEDIA.ORG/WIKI/MULTIFERROICS
- 5. WHAT IS MULTIFERROICS ? IDEA OF THE MAGNETOELECTRIC EFFECT MAGNETOELECTRICITY
- 7. MULTIFERROICS & MAGNETOELECTRIC EFFECT • Simultaneous breaking of time reversal and spatioal inversion • Plenty of multiferroics even room-temperature ones! • In hand: Ba2CoGe2O7 , Ca2CoSi2O7 , NdFe3(BO3)4 , TbFe3(BO3)4 ,CoCr2O4 , FeCr2O4 , MnCr2O4, NiV3O8 P. Curie, Journal de Physique 3, 393 (1894) „Materials should exist, which can be polarized by a magnetic field and magnetized via an electric field.”
- 8. Multiferroic state of Ba2CoGe2O7 [010] [001] [100] 21 m[110] [001] [010] [100] 4 Ba Co Ge O P421m i×4 = • Tetragonal noncentrosymmetric crystal structure V. Hutanu et al., Phys. Rev. B 84, 212101 (2011) • Magetic Co2+ ions with S=3/2 in tetrahedral oxygen cages • Easy-plane Néel antiferromagnet V. Hutanu ... and I. Kézsmárki, Phys. Rev. B 86, 104401 (2012)
- 9. Multiferroics were considered to be rare because magnetism and ferroelectricity require entirely different criteria for the materials. Several multiferroic oxides have, however, been discovered in the past few years by virtue of novel operating mechanisms, the most effective one being ferroelectricity driven by magnetism itself. Many such oxides where the magnetic and electric order parameters interact also exhibit magnetoelectric or magnetodielectric properties. Multiferroic properties arising from charge ordering are examined. The present status of BiMnO3, which is an unusual example of a ferromagnetic−ferroelectric, is presented. Some of the recent examples of magnetically induced ferroelctricity are TbMnO3, GdFeO3, SmFeO3 Cpubs.acs.org/JPCL N. R. Rao,* A. Sundaresan, and Rana Saha
- 10. In recent years, there has been remarkable interest in the synthesis and investigation of hybrid organic−inorganic materials, such as the metal−organic frameworks (MOFs), largely due to their potential applications in gas storage, catalysis, nonlinear optics, photoluminescence, and solar cells as well as their intriguing magnetic and electric properties for fundamental science study Compared with inorganic multiferroic materials of transition metal oxides, the ME effects in multiferroic MOFs are very weak and even undetectable because their electric and magnetic orders usually have different origins. Only recently reported MOF which has the ME effects in the multiferroic state of the perovskite MOF [(CH3)2NH2]Fe(HCOO)3 (FeMOF). pubs.acs.org/JACS Ying Tian, Shipeng Shen, Junzhuang Cong, Liqin Yan, Shouguo Wang, and Young Sun*
- 13. • Piezoelectric Material will generate electric potential when subjected to some kind of mechanical stress. Pierre Curie and Jacqueus Curie (brothers) discovered the piezoelectric effect in 1880.
- 14. Gabriel Lippmann in the year 1881 deduced mathematically the inverse piezoelectric effect from fundamental thermodynamic principles. The Curie brothers experimentally verified the existence of the inverse piezoelectric effect. In the inverse piezoelectric effect, an electric field is applied to a material to generate mechanical deformations
- 15. • A traditional piezoelectric ceramic is a mass of perovskite crystals. Each crystal consists of a small tetravalent metal ion, usually titanium or zirconium, in a lattice of larger divalent metal ions, usually lead or barium, and O2- ions • At temperatures below the Curie point, however, each crystal has tetragonal or rhombohedral symmetry and a dipole moment. Above the Curie point each perovskite crystal in the fired ceramic element exhibits a cubic symmetry with no dipole moment.
- 16. • Naturally occurring crystals: Berlinite (AlPO4), cane sugar, Quartz, Rochelle salt, Topaz, Tourmaline Group Minerals, and dry bone (apatite crystals) • Man-made crystals: Gallium orthophosphate (GaPO4), Langasite (La3Ga5SiO14) • Man-made ceramics: Barium titanate (BaTiO3), Lead titanate (PbTiO3), Lead zirconate titanate (Pb[ZrxTi1-x]O3 0<x<1) - More commonly known as PZT, Potassium niobate (KNbO3), Lithium niobate (LiNbO3), Lithium tantalate (LiTaO3), Sodium tungstate (NaxWO3), Ba2NaNb5O5, Pb2KNb5O15 • Polymers: Polyvinylidene fluoride (PVDF)
- 17. This is a mechanism, a piezoelectrochemical effect for the direct conversion of mechanical energy to chemical energy. This phenomenon is further applied for generating hydrogen and oxygen via direct water decomposition by means of as-synthesized piezoelectric ZnO microfibers and BaTiO3 microdendrites. Fibers and dendrites are vibrated with ultrasonic waves leading to a strain- induced electric charge development on their surface. With sufficient electric potential, strained piezoelectric fibers (and dendrites) in water triggeredthe redox reaction of water to produce hydrogen and oxygen gases. ZnO fibersunder ultrasonic vibrations showed a stoichiometric ratio of H2/O2 (2:1) initial gasproduction from pure water. This study provides a simple and cost-effectivetechnology for direct water splitting that may generate hydrogen fuels by scavenging energy wastes such as noise or stray vibrations from the environment. pubs.acs.org/JPCL Kuang-Sheng Hong,† Huifang Xu,*,† Hiromi Konishi,† and Xiaochun Li
- 18. pubs.acs.org/JPCL Kuang-Sheng Hong,† Huifang Xu,*,† Hiromi Konishi,† and Xiaochun Li
- 19. pubs.acs.org/JPCL Kuang-Sheng Hong,† Huifang Xu,*,† Hiromi Konishi,† and Xiaochun Li