WO2005009905A1 - Magnetoelectric layered-perovskite materials and electronic devices comprising the perovskites materials - Google Patents
Magnetoelectric layered-perovskite materials and electronic devices comprising the perovskites materials Download PDFInfo
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- WO2005009905A1 WO2005009905A1 PCT/KR2004/001898 KR2004001898W WO2005009905A1 WO 2005009905 A1 WO2005009905 A1 WO 2005009905A1 KR 2004001898 W KR2004001898 W KR 2004001898W WO 2005009905 A1 WO2005009905 A1 WO 2005009905A1
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- magnetoelectric
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- perovskites
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- 239000000463 material Substances 0.000 title claims abstract description 43
- 230000005291 magnetic effect Effects 0.000 claims abstract description 61
- 230000005690 magnetoelectric effect Effects 0.000 claims abstract description 29
- 230000005621 ferroelectricity Effects 0.000 claims abstract description 18
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 230000007704 transition Effects 0.000 claims abstract description 15
- 229910052691 Erbium Inorganic materials 0.000 claims abstract description 10
- 229910052688 Gadolinium Inorganic materials 0.000 claims abstract description 10
- 229910052692 Dysprosium Inorganic materials 0.000 claims abstract description 9
- 229910052693 Europium Inorganic materials 0.000 claims abstract description 9
- 229910052689 Holmium Inorganic materials 0.000 claims abstract description 9
- 229910052779 Neodymium Inorganic materials 0.000 claims abstract description 9
- 229910052772 Samarium Inorganic materials 0.000 claims abstract description 9
- 229910052771 Terbium Inorganic materials 0.000 claims abstract description 9
- 229910052775 Thulium Inorganic materials 0.000 claims abstract description 9
- 229910052769 Ytterbium Inorganic materials 0.000 claims abstract description 9
- 229910052742 iron Inorganic materials 0.000 claims abstract description 8
- 229910052747 lanthanoid Inorganic materials 0.000 claims abstract description 8
- 150000002602 lanthanoids Chemical group 0.000 claims abstract description 8
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 8
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 7
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 7
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 7
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 7
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 7
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 7
- 230000005693 optoelectronics Effects 0.000 claims abstract description 6
- 238000003860 storage Methods 0.000 claims abstract description 5
- 239000003990 capacitor Substances 0.000 claims description 27
- 239000010409 thin film Substances 0.000 description 28
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 17
- 239000000758 substrate Substances 0.000 description 15
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 description 14
- 238000000034 method Methods 0.000 description 12
- 239000010408 film Substances 0.000 description 10
- 239000010936 titanium Substances 0.000 description 10
- 239000013078 crystal Substances 0.000 description 9
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 229910052719 titanium Inorganic materials 0.000 description 8
- 229910052797 bismuth Inorganic materials 0.000 description 7
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- 230000005415 magnetization Effects 0.000 description 6
- 229910001329 Terfenol-D Inorganic materials 0.000 description 5
- 239000002131 composite material Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 229910052761 rare earth metal Inorganic materials 0.000 description 5
- RHISNCGETRBCGU-UHFFFAOYSA-N [Bi+3].[Bi+3].[O-][Mn]([O-])=O.[O-][Mn]([O-])=O.[O-][Mn]([O-])=O Chemical group [Bi+3].[Bi+3].[O-][Mn]([O-])=O.[O-][Mn]([O-])=O.[O-][Mn]([O-])=O RHISNCGETRBCGU-UHFFFAOYSA-N 0.000 description 4
- 230000005294 ferromagnetic effect Effects 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 4
- 238000000137 annealing Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000005684 electric field Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- QYIGOGBGVKONDY-UHFFFAOYSA-N 1-(2-bromo-5-chlorophenyl)-3-methylpyrazole Chemical compound N1=C(C)C=CN1C1=CC(Cl)=CC=C1Br QYIGOGBGVKONDY-UHFFFAOYSA-N 0.000 description 2
- 230000005290 antiferromagnetic effect Effects 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910001451 bismuth ion Inorganic materials 0.000 description 2
- 229910002115 bismuth titanate Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000005292 diamagnetic effect Effects 0.000 description 2
- OSCSMOVPJCIXGI-UHFFFAOYSA-N dioxido(oxo)manganese yttrium(3+) Chemical compound [Y+3].[Y+3].[O-][Mn]([O-])=O.[O-][Mn]([O-])=O.[O-][Mn]([O-])=O OSCSMOVPJCIXGI-UHFFFAOYSA-N 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- -1 oxygen ions Chemical class 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000002216 synchrotron radiation X-ray diffraction Methods 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- LCKIEQZJEYYRIY-UHFFFAOYSA-N Titanium ion Chemical compound [Ti+4] LCKIEQZJEYYRIY-UHFFFAOYSA-N 0.000 description 1
- 229910009580 YMnO Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005620 antiferroelectricity Effects 0.000 description 1
- 229910000416 bismuth oxide Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- TYIXMATWDRGMPF-UHFFFAOYSA-N dibismuth;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Bi+3].[Bi+3] TYIXMATWDRGMPF-UHFFFAOYSA-N 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 1
- LYQGMALGKYWNIU-UHFFFAOYSA-K gadolinium(3+);triacetate Chemical compound [Gd+3].CC([O-])=O.CC([O-])=O.CC([O-])=O LYQGMALGKYWNIU-UHFFFAOYSA-K 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
- C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
- C04B35/475—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on bismuth titanates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G29/00—Compounds of bismuth
- C01G29/006—Compounds containing, besides bismuth, two or more other elements, with the exception of oxygen or hydrogen
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/018—Dielectrics
- H01G4/06—Solid dielectrics
- H01G4/08—Inorganic dielectrics
- H01G4/12—Ceramic dielectrics
- H01G4/1209—Ceramic dielectrics characterised by the ceramic dielectric material
- H01G4/1218—Ceramic dielectrics characterised by the ceramic dielectric material based on titanium oxides or titanates
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/85—Piezoelectric or electrostrictive active materials
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/30—Three-dimensional structures
- C01P2002/34—Three-dimensional structures perovskite-type (ABO3)
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/77—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by unit-cell parameters, atom positions or structure diagrams
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/42—Magnetic properties
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/76—Crystal structural characteristics, e.g. symmetry
- C04B2235/768—Perovskite structure ABO3
Definitions
- the present invention relates to layered perovskite materials having magnetoelectric effects over room temperature and electronic devices comprising the magnetoelectric perovskites materials. More particularly, the present invention relates to magnetoelectric layered-perovskites materials in which bismuth, a rare earth elements, titanium, oxygen and optionally a transition elements are contained; and electronic devices comprising the perovskites materials.
- Magnetoelectric material means a material responding sensitively to both a external magnetic field and an external electric field. Accordingly, the materials generate an electric voltage upon being exposed to a magnetic field and are magnetized upon being exposed to an electric field.
- the magnetoelectric material should have large magnetic moment upon being exposed to a magnetic field . Simultaneously , it should have ferroelectricity or antiferroelectricity, which are properties indicating the induction of large electric voltage in the material upon being exposed to an electric field.
- Bismuth manganite has a ferromagnetic phase transition temperature of about 100K and a ferroelectric phase transition temperature (T ) of about 450K. Accordingly, it has large magnetic moment and ferroelectricity only below the temperature of 100K (N. A. Hill, K. M. Rabe, Physical Review B, vol. 59 pp. 8759 (1999)) [9] This kind of materials cannot be applied to actual electronic devices operated over room temperature due to its lack of magnetoelectric effect over room temperature.
- antiferromagnetic and ferroelectric yttrium manganite (YMnO ) has an antiferromagnetic phase transition temperature of 3 70-130K and a ferroelectric phase transition temperature of 570-990K, it has large magnetic moment and ferroelectricity only at a temperature not higher than 70-130K. Accordingly, yttrium manganite cannot be commercialized into the devices due to the same reason as that of bismuth manganite (A. Rlippetti, N. A. Hill, Journal of Magnetism and Magnetic Materials, vol. 236, pp. 176(2001))
- a representative magnetoelectric composite material exhibiting large magnetoelectric effects over room temperature is Terfenol (a metal having large magnetic memont)/PZT(a ferroelectric oxide)/Terfenol slabs.
- the present invention has been made for resolving the above ⁇ nentioned problems in magnetoelectric materials. It is an objective of the present invention to provide single-phase perovskite materials having i) large magnetoelectric effect originated from large magnetic moment and ferroelectricity over room temperature and ii) capability to be fabricated in the form of film.
- magnetoelectric layered perovskite materials having large magnetic moment and ferroelectricity over room temperature are provided.
- the magnetoelectric layered perovskites are characterized by Formula 1 or 2 below:
- R is a lanthanide series element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce and mixtures thereof
- T is a transition element selected from the group consisting of Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof
- x is a number of from 0J to 4
- y is a number of from 0.001 to 3.
- magnetic lanthanide series elements for example, Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, and Ce
- magnetic transition elements for example, Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta and Zr, have an ionic radius similar to that of titanium.
- these elements can easily substitute titanium atoms in the layered perovskites crystal lattice, resulting in enhancement of its magnetic moment and ferroelectric properties.
- the present inventors have developed the materials of Formulae 1 and 2 which exhibit large magnetoelectric effects originating from its large magnetic moment and enhanced ferroelectricity over room temperature.
- x is a number of 0J ⁇ 4, preferably 0J5-3, and more preferably 0.45-1.5.
- y is a number of 0.001-3, preferably 0.02-3, and more preferably 0.05-1.25.
- the layered perovskites materials of Formula 1 or 2 have large magnetoelectric effects originating from its large magnetic moment and enhanced ferroelectricity over room temperature, it can be utilized as a functional part in various electronic devices requiring magnetoelectric properties, including spintronic devices, ultra-high-density information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices, magnetic-electric transducers, and electric ⁇ nagnetic transducers, etc.
- the present inventors have adopted metal-organic sol decomposition (MOSD) technique for fabrication of capacitors based on the layered perovskites.
- MOSD metal-organic sol decomposition
- the capacitors are typically fabricated by i) desolving inorganic or organic salts of bismuth, a rare earth element, titanium, and optionally those of a transition element in a predetermined mixing ratio to form a sol, ii) coating the sol on a substrate, iii) drying the coated layer, iv) thermal annealing of the coated layer for crystallization, and v) depositing an electrically conductive electrode onto the crystallized layer.
- the present invention is not limited to this fabrication method.
- the fabrication method can be extended to various available techniques, including pulsed laser vapor deposition, chemical vapor deposition (CND), sputtering deposition and the like.
- Examples of materials for the electrically conductive electrode include gold, platinum, silver, conductive oxides and mixtures thereof. Description Of Drawings
- Figs, la to lc show the layered perovskite crystal structure of Bi R Ti T O -x x 3-y y 12 according to the present invention
- Fig. 2 shows a synchrotron XRD pattern of a Bi Gd Ti O thin film grown 3 15 0 85 3 12 onto STO (strontium titanate) substrate
- Fig. 3 shows an XRD pole figure of a Bi Gd Ti O thin film grown onto an 3 15 0 85 3 12 STO substrate
- Fig. 4 shows a synchrotron X-ray absorption fine structure (XAFS) spectrum of a Bi Gd Ti O thin film grown onto STO substrate; 3 15 0 85 3 12
- XAFS synchrotron X-ray absorption fine structure
- Fig. 5 shows room-temperature ferromagnetic properties of Bi Gd Ti O thin 3 15 0 85 3 12 film grown onto STO substrate.
- Magnetization behavior of Bi Gd Ti O thin film grown onto STO substrate 3 15 0 85 3 12 was measured through a magnetic field-magnetization reversal process.
- Rg. 5a shows details of a magnetization hysteresis loop of the Bi Gd Ti O thin film at low 3 15 0 85 3 12 external magnetic field.
- Fig. 5b shows the temperature dependence of magnetization in the Bi Gd Ti O thin film; 3 15 0 85 3 12
- Rg. 6 shows room-temperature diamagnetic properties of a Bi Ti O thin film 4 3 12 grown onto STO substrate Magnetization behavior of Bi Ti O thin film grown onto 4 3 12 STO substrate was measured through a magnetic field-magnetization reversal process
- Rg. 7a shows the ferroelectric properties of a Bi R Ti O (R is Gd, and x is 0.85) -x x 3 12 capacitor. The ferroelectric properties of it were measured through an electric field- polarization reversal process. Specifically, Rg. 7a compares electric field-polarization curves before and after 4.5 x 10 cycles of polarization reversal.
- Rg. 8 shows change in the magnetoelectric (ME) coefficient ( ⁇ ) of a Bi Gd Ti 3 15 0 85 3 O thin film grown onto Pt/TiO /SiO /Si substrate along the direction and magnitude 12 2 2 of a direct magnetic field superimposed on externally applied alternating sinusoidal magnetic field; and are ME coefficients measured upon application of direct 31 33 magnetic field perpendicular and parallel to alternating sinusoidal magnetic field, respectively.
- Example 1 Fabrication of Bi Gd Ti O film-based capacitor 3 15 0 85 1 12.
- Bi Gd Ti O film-based capacitor was fabricated in accordance with the 3 15 0 85 3 12 following procedure for determination of the magnetic properties, ferroelectric charac- tieristics, and magnetoelectric effects of the Gd-substituted layered perovskite, one of the present invention, over room temperature.
- Rrst, bismuth acetate, titanium isopropoxide and gadolinium acetate were dissolved into anhydrous acetic acid to form a homogeneous sol in which bismuth, gadolinium and titanium were contained in a molar ratio of 3J5: 0.85: 3.
- the sol was coated onto Pt/TiO /SiO /Si or STO substrates, dried, and crystallized by thermal 2 2 annealing at 700 C for 1 hr in oxygen atmosphere. Rnally, a platinum electrode was deposited onto the crystallized film for fabrication of Bi Gd Ti O capacitor. 3 15 0 85 3 12
- Rg. la to lc show the layered perovskite crystal structure of Bi R Ti T O (x is 4-x x 3-y y 12 a number of OJ-4 and y is a number of 0.001-3) according to the present invention.
- PL represents the perovskite layers
- BOL represents the bismuth oxide layers.
- Rg. lb is a projected view of the layered perovskite crystal structure of Bi R Ti 4-x x 3-y T O (x is a number of OJ-4 and y is a number of 0.001-3) onto the a-c plane
- y 12 Rg. lc is a projected view of the perovskite layer onto the a-b plane.
- Rgs. 5a and 5b The results are shown in Rgs. 5a and 5b. 1 1 was confirmed from Rgs. 5a and 5b that the Bi Gd Ti O thin film shows 3 15 0 85 3 12 ferromagnetic behavior over room temperature. This means that substitution of Bi with Gd ions cause a enhancement of magnetic moment of the layered perovskites.
- Rg. 5a shows particulars of a magnetization hysteresis loop of the Bi Gd Ti O 3 15 0 85 3 12 thin film at low external magnetic field.
- Rg. 5b shows the temperature dependence of magnetization in the Bi Gd Ti O 3 15 0 85 3 thin film . It was confirmed from Rg.
- Rgs. 7a and 7b The results are shown in Rgs. 7a and 7b.
- Rg. 7a shows the ferroelectric properties of the Bi Gd Ti O capacitor. 3 15 0 85 3 12 Specifically, Rg. 7a shows electric field-polarization curves before and after 4.5 x 10 cycles of polarization reversal.
- Rg. 7b shows the variation of switching charges and non-switching charges with increasing numbers of switching cyJe.
- the Bi Gd Ti O thin film shows excellent ferroelectric properties at room 3 15 0 85 3 12 temperature as indicated in Rgs. 7a and 7b.
- the Bi Gd Ti O thin film 3 15 0 85 3 12 capacitor shows large magnetic moment and good ferroelectric properties at room temperature.
- Rg. 8 shows changes in the room temperature magnetoelectric (ME) coefficients ( ⁇ ) of the Bi Gd Ti O capacitor along the direction and magnitude of a direct 3 15 0 85 3 12 magnetic field superimposed onto externally applied alternating sinusoidal magnetic field, and are ME coefficients measured upon application of direct magnetic 31 33 field perpendicular and parallel to alternating sinusoidal magnetic field, respectively.
- bismuth ions can be substituted with a rare earth elements (R is selected from Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof) in the Bi R Ti T O materials fabricated as described in Example 4-x x 3-y y 12 1 of the present invention.
- titanium ions can be selectively replaced with a transition elements (T is selected from Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof) in it of the present invention.
- T is selected from Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof
- the present invention provides the layered perovskites materials Bi R Ti O (x is a number of from 0.1 to 4) and Bi R Ti T O 4-x x 3 12 4-x x 3-y y (x is a number of from 0J to 4 and y is a number of from 0.001 to 3) containing 12 bismuth (Bi), a rare earth element (R) selected from Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof, titanium, and optionally a transition element (T) selected from Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof.
- R rare earth element
- T transition element
- the layered perovskites materials have large magnetoelectric effects resulting from both large magnetic moment and ferroelectricity over room temperature, they can be utilized as various types of parts in electronic devices, including spintronic devices, ultrahigh-density information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices, transducers, and etc.
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Abstract
Disclosed herein are the layered perovskites materials having magnetoelectric effects originated from large magnetic moment and ferroelectricity over room temperature. The layered perovskites material is represented by Formula 1 or 2 below: Bi4-xRxTi3O12 (1) Bi4-xRxTi3-yTyO 12 (2) wherein R is a lanthanide series element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof; T is a transition element selected from the group consisting of Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof; x is a number of from 0.1 to 4; and y is a number of from 0.001 to 3. Further disclosed are electronic devices comprising the perovskites materials. Since the perovskites materials have a magnetoelectric effects originated from large magnetic moment and ferroelectricity over room temperature, they can be utilized as various types of parts in electronic devices, including spintronic devices, information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices, transducers, etc.
Description
Description MAGNETOELECTRIC LAYERED-PEROVSKITE MATERIALS AND ELECTRONIC DEVICES COMPRISING THE PEROVSKITES MATERIALS Technical Field
[1] The present invention relates to layered perovskite materials having magnetoelectric effects over room temperature and electronic devices comprising the magnetoelectric perovskites materials. More particularly, the present invention relates to magnetoelectric layered-perovskites materials in which bismuth, a rare earth elements, titanium, oxygen and optionally a transition elements are contained; and electronic devices comprising the perovskites materials. Background Art
[2] Magnetoelectric material means a material responding sensitively to both a external magnetic field and an external electric field. Accordingly, the materials generate an electric voltage upon being exposed to a magnetic field and are magnetized upon being exposed to an electric field.
[3] Extensive researches have been recently undertaken on magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices, magnetic-electric as well as electric-magnetic transducers, and etc. For successful commercialization of these modern devices, a number of studies have been focused onto the development of the materials having large magnetoelectric effect over room temperature, which is the range of temperature for actual use of the devices.
[4] For realization of large magnetoelectric effect, the magnetoelectric material should have large magnetic moment upon being exposed to a magnetic field . Simultaneously , it should have ferroelectricity or antiferroelectricity, which are properties indicating the induction of large electric voltage in the material upon being exposed to an electric field.
[5] Since the 1890's, great efforts have been directed toward the development of homogeneous magnetoelectric materials exhibiting magnetoelectric effects. As a result, homogeneous magnetoelectric materials, such as Cr O , Pb(Fe Nb )O , BaMeF (Me 2 3 1/2 1/2 3 4 is Mn, Fe, Co or Ni), Cr BeO and BiFeO , have been found to exhibit magnetoelectric 2 4 3 effects (G Smolenskii and V. A. Ioffe, Colloque International du Magnetisme, Communication No. 71, 1958; G A. Smolenskii and I. E. Chupis, Problems in Solid State Physics (Mir Publishers, Moscow, 1984; I. H. Ismailzade, V. I. Nesternko, F. A.
Mirishli, and P. G Rustamov, Phys. Status Solidi 57, 99 (1980)) [6] However, these materials were found to have small magnetoelectric coefficient or to exhibit magnetoelectric effects only in the low temperature range below 0 C. Accordingly, they are not suitable for practical application to electronic devices. [7] One of the early developed magnetoelectric materials having both large magnetic moment and ferroelectricity is bismuth manganite (BiMnO ) 3
[8] Bismuth manganite has a ferromagnetic phase transition temperature of about 100K and a ferroelectric phase transition temperature (T ) of about 450K. Accordingly, it has large magnetic moment and ferroelectricity only below the temperature of 100K (N. A. Hill, K. M. Rabe, Physical Review B, vol. 59 pp. 8759 (1999)) [9] This kind of materials cannot be applied to actual electronic devices operated over room temperature due to its lack of magnetoelectric effect over room temperature. [10] Similarly to bismuth manganite, antiferromagnetic and ferroelectric yttrium manganite (YMnO ) has an antiferromagnetic phase transition temperature of 3 70-130K and a ferroelectric phase transition temperature of 570-990K, it has large magnetic moment and ferroelectricity only at a temperature not higher than 70-130K. Accordingly, yttrium manganite cannot be commercialized into the devices due to the same reason as that of bismuth manganite (A. Rlippetti, N. A. Hill, Journal of Magnetism and Magnetic Materials, vol. 236, pp. 176(2001))
[11] Many research efforts have been made for development of magnetoelectric composite materials having enhanced magnetoelectric effect over room temperature through mixing materials having large magnetic moment and ferrolectricity over room temperature.
[12] A representative magnetoelectric composite material exhibiting large magnetoelectric effects over room temperature is Terfenol (a metal having large magnetic memont)/PZT(a ferroelectric oxide)/Terfenol slabs.
[13] In spite of its large magnetoelectric effects over room temperature, the composite material Terfenol/PZT/Terfenol is problematic due to its complicate structure and manifestation of large magnetoelectric effect only upon specific condition. The composite represents large magnetoelectric effects only upon being exposed to a direct magnetic field over 1,000 gauss. Furthermore, metallic terfenol tend to be easily oxidized in air. This makes a fabrication of the composite material in the form of film, adequate to high-density devices, difficult. (J. G Wan, J. M. Liu, H. L. W. Chand et al. Journal of Applied Physics, Vol. 93, No. 12, pp. 9916-9919 (2003); Jungho Ryu, Shashank Priya, Kenji Uchino, and Hyoun-Ee Kim, Journal of the American Ceramic
Society, Vol. 84, No. 12, pp. 2905-2908 (2001))
[14] Thus, there is an urgent need to develop single-phase materials having i) large magnetoelectric effect originated from large magnetic moment and ferroelectricity over room temperature and ii) capability to be fabricated in the form of film. Disclosure
[15] Therefore, the present invention has been made for resolving the above ^nentioned problems in magnetoelectric materials. It is an objective of the present invention to provide single-phase perovskite materials having i) large magnetoelectric effect originated from large magnetic moment and ferroelectricity over room temperature and ii) capability to be fabricated in the form of film.
[16] It is another objective of the present invention to provide electronic devices comprising the single-phase perovskites materials.
[17] In order to accomplish the above objectives of the present invention, magnetoelectric layered perovskite materials having large magnetic moment and ferroelectricity over room temperature are provided. The magnetoelectric layered perovskites are characterized by Formula 1 or 2 below:
[18] Formula 1
[19] Bi R Ti O -x x 3 12
[20] Formula 2
[21] Bi R Ti T O -x x 3-y y 12
[22] wherein R is a lanthanide series element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce and mixtures thereof; T is a transition element selected from the group consisting of Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof; x is a number of from 0J to 4; and y is a number of from 0.001 to 3.
[23] Hereinafter, the present invention will be described in more detail.
[24] It is known that the ferroelectricity of a bismuth titanate layered perovskites material (Bi Ti O ) arises from an octahedral structure consisting of one titanium ion 4 3 12 4+ (Ti ) and six oxygen atoms in the crystal lattice. [25] However, bismuth, titanium, and oxygen ions in the layered perovskites do not endow it with large magnetic moment. [26] In order to endow the ferroelectric layered perovskites with large magnetic moment, the introduction of a element having or inducing large magnetic moment into the layered perovskites crystal is required. [27] Thus, the present inventors have adopted lanthanide series elements and transition
elements capable of inducing large magnetic moment to the layered perovskites, respectively.
[28] In selecting appropriate lanthanide series elements and transition elements, the present inventors considered various physicochemical factors : i) the stability of layered perovskites phase, ii) capability of endowment with large magnetic moment, iii) the enhancement of ferroelectricity of the layered perovskites.
[29] As a result, the present inventors have found that magnetic lanthanide series elements, for example, Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, and Ce, have an atomic valence of +3 and ionic radius similar to that of bismuth. These elements can easily substitute bismuth ions in the layered perovskites crystal, resulting in enhancement of its magnetic moment and ferroelectric properties. In addition to this, the present inventors have also found that magnetic transition elements, for example, Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta and Zr, have an ionic radius similar to that of titanium. Similarly to the lanthanide series elements, these elements can easily substitute titanium atoms in the layered perovskites crystal lattice, resulting in enhancement of its magnetic moment and ferroelectric properties. Based on these findings, the present inventors have developed the materials of Formulae 1 and 2 which exhibit large magnetoelectric effects originating from its large magnetic moment and enhanced ferroelectricity over room temperature.
[30] In Formulae 1 and 2, x is a number of 0J~4, preferably 0J5-3, and more preferably 0.45-1.5.
[31] In Formula 2, y is a number of 0.001-3, preferably 0.02-3, and more preferably 0.05-1.25.
[32] Since the layered perovskites materials of Formula 1 or 2 have large magnetoelectric effects originating from its large magnetic moment and enhanced ferroelectricity over room temperature, it can be utilized as a functional part in various electronic devices requiring magnetoelectric properties, including spintronic devices, ultra-high-density information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices, magnetic-electric transducers, and electric^nagnetic transducers, etc.
[33] The present inventors have adopted metal-organic sol decomposition (MOSD) technique for fabrication of capacitors based on the layered perovskites. Using the MOSD technique, the capacitors are typically fabricated by i) desolving inorganic or organic salts of bismuth, a rare earth element, titanium, and optionally those of a transition element in a predetermined mixing ratio to form a sol, ii) coating the sol on a
substrate, iii) drying the coated layer, iv) thermal annealing of the coated layer for crystallization, and v) depositing an electrically conductive electrode onto the crystallized layer. However, the present invention is not limited to this fabrication method. The fabrication method can be extended to various available techniques, including pulsed laser vapor deposition, chemical vapor deposition (CND), sputtering deposition and the like.
[34] Examples of materials for the electrically conductive electrode include gold, platinum, silver, conductive oxides and mixtures thereof. Description Of Drawings
[35] The above and other objectives, features, and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[36] Figs, la to lc show the layered perovskite crystal structure of Bi R Ti T O -x x 3-y y 12 according to the present invention; [37] Fig. 2 shows a synchrotron XRD pattern of a Bi Gd Ti O thin film grown 3 15 0 85 3 12 onto STO (strontium titanate) substrate; [38] Fig. 3 shows an XRD pole figure of a Bi Gd Ti O thin film grown onto an 3 15 0 85 3 12 STO substrate; [39] Fig. 4 shows a synchrotron X-ray absorption fine structure (XAFS) spectrum of a Bi Gd Ti O thin film grown onto STO substrate; 3 15 0 85 3 12
[40] Fig. 5 shows room-temperature ferromagnetic properties of Bi Gd Ti O thin 3 15 0 85 3 12 film grown onto STO substrate. [41] Magnetization behavior of Bi Gd Ti O thin film grown onto STO substrate 3 15 0 85 3 12 was measured through a magnetic field-magnetization reversal process. Rg. 5a shows details of a magnetization hysteresis loop of the Bi Gd Ti O thin film at low 3 15 0 85 3 12 external magnetic field. Fig. 5b shows the temperature dependence of magnetization in the Bi Gd Ti O thin film; 3 15 0 85 3 12
[42] Rg. 6 shows room-temperature diamagnetic properties of a Bi Ti O thin film 4 3 12 grown onto STO substrate Magnetization behavior of Bi Ti O thin film grown onto 4 3 12 STO substrate was measured through a magnetic field-magnetization reversal process; [43] Rg. 7a shows the ferroelectric properties of a Bi R Ti O (R is Gd, and x is 0.85) -x x 3 12 capacitor. The ferroelectric properties of it were measured through an electric field- polarization reversal process. Specifically, Rg. 7a compares electric field-polarization curves before and after 4.5 x 10 cycles of polarization reversal. Rg. 7b shows the variation of switching charges and non-switching charges with increasing numbers of
switching cycle; [44] Rg. 8 shows change in the magnetoelectric (ME) coefficient (α) of a Bi Gd Ti 3 15 0 85 3 O thin film grown onto Pt/TiO /SiO /Si substrate along the direction and magnitude 12 2 2 of a direct magnetic field superimposed on externally applied alternating sinusoidal magnetic field; and are ME coefficients measured upon application of direct 31 33 magnetic field perpendicular and parallel to alternating sinusoidal magnetic field, respectively. Mode for Invention
[45] The following examples are provided to assist further understanding of the present invention.
[46] However, these examples are given for the purpose of illustration. Thus, these should not to be interpreted as limiting the scope of the invention.
[47] Example 1 : Fabrication of Bi Gd Ti O film-based capacitor 3 15 0 85 1 12.
[48] Bi Gd Ti O film-based capacitor was fabricated in accordance with the 3 15 0 85 3 12 following procedure for determination of the magnetic properties, ferroelectric charac- tieristics, and magnetoelectric effects of the Gd-substituted layered perovskite, one of the present invention, over room temperature. [49] Rrst, bismuth acetate, titanium isopropoxide and gadolinium acetate were dissolved into anhydrous acetic acid to form a homogeneous sol in which bismuth, gadolinium and titanium were contained in a molar ratio of 3J5: 0.85: 3. The sol was coated onto Pt/TiO /SiO /Si or STO substrates, dried, and crystallized by thermal 2 2 annealing at 700 C for 1 hr in oxygen atmosphere. Rnally, a platinum electrode was deposited onto the crystallized film for fabrication of Bi Gd Ti O capacitor. 3 15 0 85 3 12
[50] Comparative Example 1 : Fabrication of Bi Ti O capacitor 4- 2- 12-
[51] Bismuth acetate and titanium isopropoxide were dissolved in anhydrous acetic acid to form a homogeneous sol in which bismuth and titanium were contained in a molar ratio of 4: 3. The sol was coated onto Pt/TiO /SiO /Si or STO substrates, dried, and 2 2 crystallized by thermal annealing at 700 C for lhr in oxygen atmosphere. Rnally, a platinum electrode was deposited onto the crystallized film for fabrication of Bi Ti O 4 3 12 capacitor. [52] Hereinafter, the present invention will be explained in more detail with reference to the accompanying drawings. [53] Rgs. la to lc show the layered perovskite crystal structure of Bi R Ti T O (x is 4-x x 3-y y 12 a number of OJ-4 and y is a number of 0.001-3) according to the present invention. [54] In Rg. la, PL represents the perovskite layers, and BOL represents the bismuth
oxide layers. [55] Rg. lb is a projected view of the layered perovskite crystal structure of Bi R Ti 4-x x 3-y T O (x is a number of OJ-4 and y is a number of 0.001-3) onto the a-c plane, and y 12 Rg. lc is a projected view of the perovskite layer onto the a-b plane. [56] As shown in Rgs. la to lc, Bi atoms located in the perovskite layers (PL) are mainly substituted with rare earth elements, and Ti atoms located in the perovskite layers are mainly substituted with transition elements. [57] The crystallization behavior of the Bi Gd Ti O film on STO substrate was 3 15 0 85 3 12 analyzed by using a synchrotron x-ray diffraction technique. As shown in Rg. 2, it was confirmed that Gd ions effectively substitutes Bi ions in the bismuth titanate layered perovskites crystal without a formation of secondary phases. [58] Rg. 3 shows an XRD pole figure of the Bi Gd Ti O thin film prepared onto 3 15 0 85 3 12 STO substrate. [59] This figure clearly demonstrates that the Bi Gd Ti O thin film has a uniform 3 15 0 85 3 12 in-plane orientation on STO substrate. [60] Rg. 4 shows a synchrotron XAFS spectrum of the Bi Gd Ti O thin film 3 15 0 85 3 12 prepared onto STO substrate . [61] Gd in the Bi Gd Ti O thin film has an atomic valence of +3 as apparent from 3 15 0 85 3 12 Rg. 4. This also indicates that the Gd is dissolved into the layered perovskite crystal without a formation of secondary phases. [62] The magnetic properties of the Bi Gd Ti O thin film were measured through a 3 15 0 85 3 12 magnetic field-magnetization reversal process. The results are shown in Rgs. 5a and 5b. 1 1 was confirmed from Rgs. 5a and 5b that the Bi Gd Ti O thin film shows 3 15 0 85 3 12 ferromagnetic behavior over room temperature. This means that substitution of Bi with Gd ions cause a enhancement of magnetic moment of the layered perovskites. [63] Rg. 5a shows particulars of a magnetization hysteresis loop of the Bi Gd Ti O 3 15 0 85 3 12 thin film at low external magnetic field. [64] Rg. 5b shows the temperature dependence of magnetization in the Bi Gd Ti O 3 15 0 85 3 thin film . It was confirmed from Rg. 5b that the ferromagnetic properties of the Bi 12 Gd Ti O thin film are maintained over 400K (127 C) or above. In Rg. 5b, ZFC 3 15 0 85 3 12 refers to zero field cooling, and FC refers to field cooling. [65] On the other hand, the room temperature magnetic properties of the Bi Ti O thin 4 3 12 film, fabricated in Comparative Example 1, were measured. The results are shown in Rg. 6. It was confirmed that the Bi Ti O thin film is diamagnetic at room 4 3 12 temperature. This means that Bi Ti O thin film has low magnetic moment. 4 3 12
[66] The room temperature ferroelectric properties of the Bi Gd Ti O capacitor 3 15 0 85 3 12 were measured through an electric field-polarization reversal process. The results are shown in Rgs. 7a and 7b. [67] Rg. 7a shows the ferroelectric properties of the Bi Gd Ti O capacitor. 3 15 0 85 3 12 Specifically, Rg. 7a shows electric field-polarization curves before and after 4.5 x 10 cycles of polarization reversal. [68] Rg. 7b shows the variation of switching charges and non-switching charges with increasing numbers of switching cyJe. [69] The Bi Gd Ti O thin film shows excellent ferroelectric properties at room 3 15 0 85 3 12 temperature as indicated in Rgs. 7a and 7b. [70] As shown in Rgs. 5a and 5b, and Rgs. 7a and 7b, the Bi Gd Ti O thin film 3 15 0 85 3 12 capacitor shows large magnetic moment and good ferroelectric properties at room temperature.
[71] For determination of magnetoelectric effect at room temperature, the magnetoelectric coefficients of the capacitor were measured at room temperature by using alternating sinusoidal and direct magnetic fields. The results are shown in Rg. 8.
[72] Rg. 8 shows changes in the room temperature magnetoelectric (ME) coefficients (α) of the Bi Gd Ti O capacitor along the direction and magnitude of a direct 3 15 0 85 3 12 magnetic field superimposed onto externally applied alternating sinusoidal magnetic field, and are ME coefficients measured upon application of direct magnetic 31 33 field perpendicular and parallel to alternating sinusoidal magnetic field, respectively. [73] As shown in Rg. 8, when an alternating sinusoidal magnetic field having the amplitude of 50 gauss and a frequency of 30 kHz was applied in the direction (out-of-plane direction) vertical to the Pt/ Bi Gd Ti O thin film/Pt capacitor, the 3 15 0 85 3 12 Bi Gd Ti O capacitor had a magnetoelectric coefficient ( ) of 36.5 N/cm-Oe. On 3 15 0 85 3 12 31 the other hand, when an alternating current magnetic field having the amplitude of 50 gauss and a frequency of 30 kHz was applied in the direction (in-plane direction) horizontal to the Pt/ Bi Gd Ti O thin film/Pt capacitor, the Bi Gd Ti O 3 15 0 85 3 12 3 15 0 85 3 12 capacitor had a magnetoelectric coefficient ( ) of 2.5 N/cm-Oe. 33
[74] These results indicate that the Pt/Bi Gd Ti O thin film/Pt capacitor has large 3 15 0 85 3 12 anisotropic magnetoelectric effects. [75] In conclusion, the Bi Gd Ti O thin film capacitor fabricated as described in 3 15 0 85 3 12 Example 1 shows large magnetoelectric effects over room temperature. It is originated from its large magnetic moment and ferroelectric properties as shown in Rgs. 5a and 5b, and Rgs. 7a and 7b, as well as Rg. 8.
[76] In contrast to Pt/Bi Gd Ti O thin film Pt capacitor, the ferroelectric Bi Ti O 3 15 0 85 3 12 4 3 12 thin film capacitor shows small magnetic moment, resulting in poor magnetoelectric effects. [77] Although the foregoing example of the present invention illustrated only the Bi 3 15 Gd Ti O capacitor among Bi R Ti T O (x is a number of 1-4 and y is a number 0 85 3 12 4-x x 3-y y 12 of 0.001-3) capacitors, it should be understood that the scope of the present invention is not limited to the material wherein R is Gd and x is 0.85. [78] As described above, bismuth ions can be substituted with a rare earth elements (R is selected from Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof) in the Bi R Ti T O materials fabricated as described in Example 4-x x 3-y y 12 1 of the present invention. Simultaneously, titanium ions can be selectively replaced with a transition elements (T is selected from Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof) in it of the present invention. Of course, it will be appreciated by any person skilled in this art that the present invention can be variously modified and altered within the technical concept of the present invention. [79] As apparent from the above description, the present invention provides the layered perovskites materials Bi R Ti O (x is a number of from 0.1 to 4) and Bi R Ti T O 4-x x 3 12 4-x x 3-y y (x is a number of from 0J to 4 and y is a number of from 0.001 to 3) containing 12 bismuth (Bi), a rare earth element (R) selected from Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof, titanium, and optionally a transition element (T) selected from Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof. Since the layered perovskites materials have large magnetoelectric effects resulting from both large magnetic moment and ferroelectricity over room temperature, they can be utilized as various types of parts in electronic devices, including spintronic devices, ultrahigh-density information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices, transducers, and etc.
Claims
[1] A layered perovskites material having magnetoelectric effects originated from large magnetic moment and ferroelectricity over room temperature, represented by Formula 1 below: Bi R Ti O (1) 4-x x 3 12 wherein R is a element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof; and x is a number of from 0.1 to 4.
[2] The layered perovskites material according to claim 1, wherein, in Formula 1, x is a number of 0.45-1.5.
[3] A layered perovskites material having magnetoelectric effects originated from large magnetic moment and ferroelectricity over room temperature, represented by Formula 2 below: Bi R Ti T O (2) 4-x x 3-y y 12 wherein R is a element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof; and T is a element selected from the group consisting of Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof; x is a number of from 0J to 4; and y is a number of from 0.001 to 3.
[4] The layered perovskites material according to claim 3, wherein, in Formula 2, x is a number of 0J~1.5 and y is a number of 0.05-1J5.
[5] An electronic device comprising a capacitor wherein the capacitor is composed of the layered perovskites material having magnetoelectric effects originated from large magnetic moment and ferroelectricity over room temperature, represented by Formula 1 below: Bi R Ti O (1) 4-x x 3 12 wherein R is a lanthanide series element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof; and x is a number of from 0.1 to 4.
[6] An electronic device comprising a capacitor wherein the capacitor is composed of the layered perovskites material having magnetoelectric effects originated from large magnetic moment and ferroelectricity over room temperature, represented by Formula 2 below: Bi R Ti T O (2) 4-x x 3-y y 12
wherein R is a lanthanide series element selected from the group consisting of Nd, Gd, Pr, Pm, Sm, Eu, Er, Tm, Tb, Yb, Dy, Ho, Er, Ce, and mixtures thereof; and T is a transition element selected from the group consisting of Co, Ni, Fe, Mn, W, V, Nb, Mo, Ta, Zr and mixtures thereof; x is a number of from 0J to 4; and y is a number of from 0.001 to 3.
[7] The electronic device according to claim 5, wherein the electronic device is selected from the group consisting of spintronic devices, information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices and transducers.
[8] The electronic device according to claim 6, wherein the electronic device is selected from the group consisting of spintronic devices, information storage devices, magnetic-electric sensors, magnetic sensors, electric sensors, optoelectronic devices, microwave electronic devices and transducers.
[9] The electronic device according to claim 5, wherein the electronic device utilizes magnetoelectric effects.
[10] The electronic device according to claim 6, wherein the electronic device utilizes magnetoelectric effects.
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KR1020030061553A KR101054012B1 (en) | 2003-09-03 | 2003-09-03 | Materials having room temperature ferromagnetic and ferroelectric and magnetoelectric effects and electronic devices including the same |
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CN101077837B (en) * | 2007-05-18 | 2010-05-19 | 中国科学院上海硅酸盐研究所 | Neodymium and vanadium composite doping bismuth titanate powder and preparation method thereof |
EP2878447A1 (en) * | 2010-03-12 | 2015-06-03 | Seiko Epson Corporation | Piezoelectric element |
CN109665833A (en) * | 2018-12-12 | 2019-04-23 | 西北工业大学 | A kind of method of more iron composite materials and the flexible more iron composite materials of preparation |
CN109704765A (en) * | 2019-03-07 | 2019-05-03 | 哈尔滨工业大学 | High densification ferroelectric ceramics and preparation method thereof with quasi- homotype crystal phase structure |
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CN101077837B (en) * | 2007-05-18 | 2010-05-19 | 中国科学院上海硅酸盐研究所 | Neodymium and vanadium composite doping bismuth titanate powder and preparation method thereof |
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CN109665833A (en) * | 2018-12-12 | 2019-04-23 | 西北工业大学 | A kind of method of more iron composite materials and the flexible more iron composite materials of preparation |
CN109704765A (en) * | 2019-03-07 | 2019-05-03 | 哈尔滨工业大学 | High densification ferroelectric ceramics and preparation method thereof with quasi- homotype crystal phase structure |
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