CN101497987A - Apparatus for preparing polycrystal ferriferrous oxide film by facing-target reactive sputtering and operation method - Google Patents

Apparatus for preparing polycrystal ferriferrous oxide film by facing-target reactive sputtering and operation method Download PDF

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CN101497987A
CN101497987A CNA2009100681261A CN200910068126A CN101497987A CN 101497987 A CN101497987 A CN 101497987A CN A2009100681261 A CNA2009100681261 A CN A2009100681261A CN 200910068126 A CN200910068126 A CN 200910068126A CN 101497987 A CN101497987 A CN 101497987A
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target
subtend
sputter
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sputtering
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白海力
申俊杰
李鹏
米文博
姜恩永
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Tianjin University
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Abstract

The invention relates to a preparation method of a facing-target reactive sputtering polycrystalline ferroferric oxide film, which adopts a DPS-III model ultrahigh vacuum facing-target magnetron sputtering film coating machine produced in Shenyang scientific instrument development center of Chinese academy of sciences. The preparation method adopts a facing-target DC magnetron reactive sputtering technique, achieves the aim of controlling the oxygen partial pressure in a vacuum chamber by controlling the flow ratio of oxygen and argon and is matched with appropriate DC sputtering power, and under the condition of room temperature, a polycrystalline ferroferric oxide film is prepared on the substrates of monocrystal silicon, monocrystal sodium chloride, glass, polyester, and the like. The preparation method of polycrystalline Fe3O4 film has the advantages of preparation in room temperature, simple target selection, high target using rate, and the like and has wide application value on the preparation of relevant spintronics components for storing and reading magnetic information, and the like.

Description

The equipment and the working method of subtend target response sputter polycrystal ferriferrous oxide film
Technical field
The present invention relates to a kind of equipment and working method of subtend target response sputter polycrystal ferriferrous oxide film, more specifically, is a kind of room temperature condition preparation, simple and high preparation method of target utilization of target selection of relating to.
Background technology
In recent years, owing to have great application prospect in the magnetic information storage with aspect reading, the spintronics material receives much concern.Nobel Prize in physics in 2007 has been authorized initiator Albert Fert and two professors of Peter Gr ü nberg of spintronics.Now, the electric current that how to obtain high spin-polarization remains one of the hot issue in spintronics field.Only there is the density of electronic states of a spin direction in semi-metallic near Fermi surface, so have 100% spin polarizability, can be used as the spin injecting material.Common semi-metallic has NiMnSb, La 1-xCa xMnO 3, Sr 2FeMoO 6, CrO 2And Fe 3O 4Deng.
Fe 3O 4Depress at room temperature and standard atmosphere and to have a cube inverse spinel structure, lattice parameter is a=8.396
Figure A200910068025D0003112506QIETU
In the unit cell of spinel structure, by four O 2-The tetrahedron center that forms is called as the A position; By six O 2-The octahedral center that forms is called as the B position.Ion on the inferior lattice of A and B position all is that ferromegnetism is arranged, and the magnetic moment of A position and B interdigit then passes through O 2-Superexchange form antiferromagnetic arrangement, form ferrimagnetism.
Fe 3O 4Fermi surface be positioned at the downward t of spin 2gThe conduction subband.Owing to have the continuous advantage such as adjustable of high Curie temperature (858K) and resistivity, can be used as the spin injection source of spinning and injecting to semi-conductor, be the ideal candidates material of MTJ, Spin Valve isospin electronics device, thereby be subjected to paying close attention to widely.
Relevant polycrystalline Fe 3O 4The existing relevant report of the method for film preparation mainly concentrates on molecular beam epitaxy and pulsed laser deposition etc. on the quite harsh method of requirement for experiment condition.But suitability for industrialized production upper film preparation methods mainly is a magnetron sputtering method at present.Prepare polycrystalline Fe at existing magnetron sputtering method 3O 4In the report of film, have following problem: (1) needs the substrate heating, has reported that such as people such as J.M.D.Coey need heat 500 ℃ of ability in the single crystalline Si substrate obtains polycrystalline Fe in the document of 734 pages of Appl.Phys.Lett.1998 the 72nd volumes 3O 4Film; (2) required sputtering target material more complicated needs to adopt α-Fe such as people such as J.K.Tang report in the document of 7690 pages of J.Appl.Phys.2001 the 89th volumes 2O 3Target, people such as M.Ziese report in the document of 415 pages of Eur.Phys.J.B2002 the 28th volumes needs to adopt the Fe of strict stoicheiometry 3O 4Target; (3) lower target utilization has reported that the method (the Fe target is as sputtering target material) that adopts single target response sputter has prepared polycrystalline Fe such as people such as H.Liu in the document of 2950 pages of 2003 the 36th volumes of J.Phys.D 3O 4Film, but because the characteristics that single target magnetic control sputtering system magnetic line of force distributes have determined lower target utilization.Accompanying drawing 1 has provided the target usage degree comparison diagram of single target magnetic control sputtering system and subtend target magnetic control sputtering system, the target on the right is the employed target of facing targets sputtering method, the left side is the employed target of single target magnetic control sputtering method, can find out obviously that the employed target utilization of subtend target magnetic control sputtering method is higher.Present breadboard magnetron sputtering method mostly is single target greatly, and the someone adopts subtend target magnetic control sputtering equipment successfully to prepare polycrystalline Fe as yet 3O 4The report that the film aspect is relevant.The present invention explores by experiment, adopts commercially available DPS-III type ultrahigh vacuum(HHV) subtend target magnetic control sputtering coating equipment successfully to prepare polycrystalline Fe first 3O 4Film.
Summary of the invention
From the angle of suitability for industrialized production, need develop room temperature condition preparation, the simple and high preparation polycrystalline Fe of target rate of utilization of target selection 3O 4The magnetron sputtering method of film.The present invention is promptly from above several angles, developed the method that subtend target response sputtering method prepares polycrystal ferriferrous oxide film.
The present invention is at preparation polycrystalline Fe 3O 4During film, the base material that is adopted has comprised glass, polyester, single crystalline NaCl, single crystalline Si etc., has all prepared isotropic polycrystalline Fe 3O 4Film.
Concrete preparation method of the present invention realizes through following steps:
The equipment of subtend target response sputter polycrystal ferriferrous oxide film of the present invention is the DPS-III type ultrahigh vacuum(HHV) subtend target magnetic control sputtering coating equipment that adopts scientific instrument development center, Chinese Academy of Sciences Shenyang to produce.
The method of the equipment of subtend target response sputter polycrystal ferriferrous oxide film is characterized in that step is as follows:
1) a pair of purity being installed on the target head of the subtend of coating equipment is 99.99% Fe target, each one on two target heads, and a N utmost point as magnetic line of force, the other end is the S utmost point, and the thickness of target is 0.5-3mm, and diameter is 60mm;
2) with behind the substrate material surface contaminant removal, will be installed on the midperpendicular of subtend target line, the vertical range of two Fe target lines of substrate and subtend target is 4-6cm;
3) unlatching DPS-III subtend target magnetic control sputtering equipment successively starts the one-level mechanical pump and the secondary molecular pump vacuumizes, and vacuum tightness is better than 8 * 10 at the bottom of the back of the body of sputtering chamber -6Pa;
4) be that 99.999% sputter gas argon gas and oxygen feed vacuum chamber with purity, wherein argon flow amount is 100sccm, and oxygen flow is 1.8-2.2sccm, the vacuum tightness of sputtering chamber is remained on 0.5-2.0Pa, and stablized 5 minutes;
5) open shielding power supply, apply the electric current of 0.05-0.35A and the volts DS of 1200-1450V on a pair of Fe target, pre-sputter 15 minutes waits for that sputtering current and voltage are stable;
6) treat that subtend target surface oxidation is stable after, the plate washer of opening between Fe target and the substrate begins sputter, substrate position is fixed, and does not heat;
7) after sputter finishes, close shielding power supply, stop to feed sputter gas, close pumped vacuum systems then, charge into nitrogen, open vacuum chamber, take out sample to vacuum chamber.
The base material that is adopted has comprised glass, polyester, single crystalline NaCl or single crystalline Si.
Polycrystalline Fe involved in the present invention 3O 4Method for manufacturing thin film has room temperature condition preparation, target is selected simple and target rate of utilization advantages of higher, in the magnetic information storage with read in the preparation of isospin electronics related device and be with a wide range of applications.
For confirming the embodiment of the best of the present invention, we change series to the prepared oxygen flow of the present invention, and (1.8-2.2sccm) film has carried out X-ray diffraction, the x-ray photoelectron power spectrum, Raman spectrum, the analysis of transmission electron microscope and scanning electronic microscope, and adopt PPMS that the magnetic property and the electrical property of film are analyzed.
Prepare polycrystalline Fe with other magnetron sputterings 3O 4The method of film is compared, and the preparation method of subtend target response sputter polycrystal ferriferrous oxide film involved in the present invention mainly has following three advantages:
1, the preparation condition of room temperature, with people such as J.M.D.Coey base reservoir temperature of reporting in the document of 734 pages of Appl.Phys.Lett.1998 the 72nd volumes is that 500 ℃ work is compared, and substrate involved in the present invention is not heated can be so that this preparation method be compatible with existing semiconductor technology.
2, target is selected more simply, report needs use α-Fe with people institute in the document of 7690 pages of J.Appl.Phys.2001 the 89th volumes such as J.K.Tang 2O 3People such as target and M.Ziese is the Fe that needs to use strict stoicheiometry that reports in the document of 415 pages of Eur.Phys.J.B2002 the 28th volumes 3O 4Target is compared, and target involved in the present invention is the Fe target that single-element constitutes, and by under argon gas and oxygen mix atmosphere condition, adopts the method for reactive sputtering to obtain polycrystalline Fe 3O 4Film, easier acquisition in actual industrial production.
3, the service efficiency of target is higher, report that with people such as H.Liu the single target response sputtering method that is adopted compares in the document of 2950 pages of 2003 the 36th volumes of J.Phys.D, subtend target response sputtering method has higher target rate of utilization, Fig. 1 has provided the target usage degree comparison diagram of single target magnetic control sputtering system and subtend target magnetic control sputtering system, the target utilization that can obviously find out subtend target magnetic control sputtering system is higher, practicability and effectiveness more in actual production.
Description of drawings
Fig. 1 is used target of the present invention and the usage degree comparison diagram that adopts the used target of single target magnetic control sputtering, and the target on the right is the employed target of subtend target, and the left side is the employed target of single target.
1.8,1.9,2.0,2.1,2.2sccm Fig. 2 is the X-ray diffractogram of the film for preparing under different oxygen flow conditions of the present invention, and (a) ~ (e) pairing oxygen flow is respectively:.
Fig. 3 is that the present invention is prepared polycrystalline Fe under the 2.0sccm condition at oxygen flow 3O 4The x-ray photoelectron power spectrum of film.
Fig. 4 is that the present invention is prepared polycrystalline Fe under the 2.0sccm condition at oxygen flow 3O 4The Raman spectrum of film, wherein solid line is prepared polycrystalline Fe among the embodiment 2 3O 4The Raman collection of illustrative plates of film, dotted line is Fe 3O 4Standard Raman collection of illustrative plates.
Fig. 5 is that the present invention is prepared polycrystalline Fe under the 2.0sccm condition at oxygen flow 3O 4The scanning electronic microscope of film (a) is orthographic plan, (b) is sectional drawing.
Fig. 6 is that the present invention is prepared polycrystalline Fe under the 2.0sccm condition at oxygen flow 3O 4The room temperature magnetic hysteresis loop of film, the illustration in the upper right corner are polycrystalline Fe 3O 4The gradually saturated synoptic diagram of the specific magnetising moment under the film High-Field.
Embodiment
According to structure and property analysis that we carry out sample prepared among the present invention, the preferred forms with subtend target response sputter polycrystal ferriferrous oxide film preparation method is described in detail below:
Embodiment 1
1, the DPS-III type ultrahigh vacuum(HHV) subtend target magnetic control sputtering coating equipment that adopts scientific instrument development center, Chinese Academy of Sciences Shenyang to produce, the a pair of purity of installation is 99.99% Fe target on the target head of subtend, each one on two target heads, a N utmost point as magnetic line of force, the other end is the S utmost point.The thickness of target is 3mm, and diameter is 60mm;
2, base material glass is removed surface impurity by modes such as ultrasonic wave after, substrate is installed on the midperpendicular of subtend target line, the vertical range of two Fe target lines of substrate and subtend target is about 5cm;
3, unlatching DPS-III subtend target magnetic control sputtering equipment successively starts the one-level mechanical pump and the secondary molecular pump vacuumizes, and vacuum tightness is better than 8 * 10 at the bottom of the back of the body of sputtering chamber -6Pa;
4, be that 99.999% sputter gas argon gas and oxygen feed vacuum chamber with purity, wherein argon flow amount is 100sccm, and oxygen flow is 1.8sccm, the vacuum tightness of sputtering chamber is remained on 0.5Pa, and stablized 5 minutes;
5, open shielding power supply, apply the electric current of 0.05A and the volts DS about 1200V on a pair of Fe target, pre-sputter 15 minutes waits for that sputtering current and voltage are stable;
6, treat that subtend target surface oxidation is stable after, promptly sputtering power stable after, the plate washer of opening between Fe target and the substrate begins sputter, substrate position is fixed, and does not heat;
7, after sputter finishes, close shielding power supply, stop to feed sputter gas, close pumped vacuum systems then, charge into nitrogen, open vacuum chamber, take out sample to vacuum chamber.
Embodiment 2:
Step is identical with embodiment 1, and different is: the target thickness in the step 1 becomes 0.5mm; The vertical range of two Fe target lines of substrate and subtend target is 4cm in the step 2, and substrate material becomes polyester, single crystalline NaCl or single crystalline Si by glass; Oxygen flow is 2.0sccm in the step 4, and the vacuum tightness of sputtering chamber is remained on 1.0Pa; On hitting, step 6 applies the electric current of 0.35A and the volts DS of 1350V;
Embodiment 3:
Step is identical with embodiment 1, and different is: the target thickness in the step 1 becomes 2mm; The vertical range of two Fe target lines of substrate and subtend target is 6cm in the step 2, and substrate material becomes polyester, single crystalline NaCl or single crystalline Si by glass; Oxygen flow is 2.2sccm in the step 4, and the vacuum tightness of sputtering chamber is remained on 2Pa; On hitting, step 6 applies the electric current of 0.2A and the volts DS of 1450V;
Fig. 2 has provided embodiment 1 among the present invention, the X-ray diffractogram of embodiment 2 and embodiment 3 prepared film under different oxygen flow conditions, and as can be seen from the figure, when oxygen flow was 1.8sccm (a), film was α-Fe, FeO and Fe 3O 4Mixed phase, be not optimum preparating condition, along with the increase gradually (1.9 of oxygen flow, 2.0,2.1sccm respectively corresponding (b)-(d)), α-Fe and FeO dephasign disappear, after oxygen flow continues to increase again (2.2sccm (e)), the intensity of diffraction peak weakens to some extent.We can judge that optimum preparating condition is embodiment 2 from the result of X-ray diffraction, and oxygen flow is 1.9-2.1sccm.
Its microtexture that we have also adopted x-ray photoelectron power spectrum, Raman spectrum, scanning electron microscopy study; And adopt vibrating sample magnetometer to measure the magnetic property of sample, further confirmed polycrystalline Fe 3O 4The best preparation method of film.
It is the x-ray photoelectron power spectrum and the Raman spectrum of 2.0sccm sample that Fig. 3 and Fig. 4 have provided oxygen flow.Because γ-Fe 2O 3And Fe 3O 4Have identical crystalline structure and close lattice parameter, thus from X-ray diffractogram, can not determine the chemical constitution of film fully, so we are that the sample of 2.0sccm has carried out x-ray photoelectron power spectrum and Raman spectrum analysis to oxygen flow.In the x-ray photoelectron power spectrum, do not observe into the 719eV place corresponding to γ-Fe 2O 3Satellites, in Raman spectrum, do not observe yet and be positioned at 700cm -1Locate corresponding γ-Fe 2O 3Diaphragm.These two kinds of measuring results show that all prepared film is the Fe of pure phase among the present invention 3O 4
Fig. 5 is the scanning electron microscope image of prepared film under the 2.0sccm condition for oxygen flow, from orthographic plan (a) as can be seen thickness be the particle size of 750nm film probably about 50nm, the growth for Thin Film pattern is a columnar growth as can be seen from sectional drawing (b).
It is the room temperature magnetic hysteresis loop of prepared film under the 2.0sccm condition, as can be seen from the figure polycrystalline Fe that Fig. 6 has provided oxygen flow 3O 4The saturation magnetization of film is approximately 300emu/cm 3, consistent with the bibliographical information value.
The equipment and the working method of subtend target response sputter polycrystal ferriferrous oxide film involved in the present invention, have room temperature condition preparation, target is selected simple and target rate of utilization advantages of higher, in the magnetic information storage with read in the preparation of isospin electronics related device and be with a wide range of applications.The method that the present invention proposes, be described by on-the-spot preferred embodiment, person skilled obviously can be in not breaking away from content of the present invention, spirit and scope to structure as herein described with the preparation method changes or suitably change and combination, realize the technology of the present invention.Special needs to be pointed out is, the replacement that all are similar and change apparent to those skilled in the artly, they are regarded as being included in spirit of the present invention, scope and the content.

Claims (3)

1. the equipment of a subtend target response sputter polycrystal ferriferrous oxide film is characterized in that the DPS-III type ultrahigh vacuum(HHV) subtend target magnetic control sputtering coating equipment that adopts scientific instrument development center, Chinese Academy of Sciences Shenyang to produce.
2. the method for the equipment of subtend target response sputter polycrystal ferriferrous oxide film as claimed in claim 1 is characterized in that step is as follows:
1) a pair of purity being installed on the target head of the subtend of coating equipment is 99.99% Fe target, each one on two target heads, and a N utmost point as magnetic line of force, the other end is the S utmost point, and the thickness of target is 0.5-3mm, and diameter is 60mm;
2) with behind the substrate material surface contaminant removal, will be installed on the midperpendicular of subtend target line, the vertical range of two Fe target lines of substrate and subtend target is 4-6cm;
3) unlatching DPS-III subtend target magnetic control sputtering equipment successively starts the one-level mechanical pump and the secondary molecular pump vacuumizes, and vacuum tightness is better than 8 * 10 at the bottom of the back of the body of sputtering chamber -6Pa;
4) be that 99.999% sputter gas argon gas and oxygen feed vacuum chamber with purity, wherein argon flow amount is 100sccm, and oxygen flow is 1.8-2.2sccm, the vacuum tightness of sputtering chamber is remained on 0.5-2.0Pa, and stablized 5 minutes;
5) open shielding power supply, apply the electric current of 0.05-0.35A and the volts DS of 1200-1450V on a pair of Fe target, pre-sputter 15 minutes waits for that sputtering current and voltage are stable;
6) treat that subtend target surface oxidation is stable after, the plate washer of opening between Fe target and the substrate begins sputter, substrate position is fixed, and does not heat;
7) after sputter finishes, close shielding power supply, stop to feed sputter gas, close pumped vacuum systems then, charge into nitrogen, open vacuum chamber, take out sample to vacuum chamber.
3. method as claimed in claim 2 is characterized in that the base material that is adopted has comprised glass, polyester, single crystalline NaCl or single crystalline Si.
CNA2009100681261A 2009-03-13 2009-03-13 Apparatus for preparing polycrystal ferriferrous oxide film by facing-target reactive sputtering and operation method Pending CN101497987A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101705474B (en) * 2009-12-15 2011-03-23 天津大学 Preparation method of iron nitride film with strong Hall effect
CN104404464A (en) * 2014-11-25 2015-03-11 天津大学 Preparation method of epitaxial lanthanum strontium cobalt oxide film based on radio-frequency reactive sputtering

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101705474B (en) * 2009-12-15 2011-03-23 天津大学 Preparation method of iron nitride film with strong Hall effect
CN104404464A (en) * 2014-11-25 2015-03-11 天津大学 Preparation method of epitaxial lanthanum strontium cobalt oxide film based on radio-frequency reactive sputtering

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