共查询到20条相似文献,搜索用时 15 毫秒
1.
V. A. Seredkin S. V. Stolyar G. I. Frolov V. Yu. Yakovchuk 《Technical Physics Letters》2004,30(10):820-822
A new principle of data writing and erasing is proposed based on the exchange coupling between magnetic layers with mutually
orthogonal orientations of the effective magnetization. The new method provides for a significant decrease in energy consumption.
The possibility of using bilayer magnetic films of the (rare earth metal-transition metal)/NiFe type possessing unidirectional
anisotropy as the media for thermomagnetic writing and erasing of magnetooptical data is studied. 相似文献
2.
R. S. Iskhakov V. A. Seredkin S. V. Stolyar V. Yu. Yakovchuk G. I. Frolov G. V. Bondarenko L. A. Chekanova V. V. Polyakov 《Technical Physics Letters》2008,34(7):577-580
The dependence of the unidirectional anisotropy in a DyCo/NiFe bilayer system on the thickness of the magnetically soft layer
has been studied using dynamic and static techniques. The magnitude of the exchange interaction between layers evaluated using
the ferromagnetic resonance method is two times that determined from an analysis of the hysteresis loops. It is established
that this difference is related to features of the magnetic microstructure of the DyCo layer. 相似文献
3.
G. I. Frolov S. Ya. Kiparisov V. A. Seredkin K. P. Polyakova G. S. Patrin V. S. Zhigalov A. D. Balaev 《Technical Physics Letters》2014,40(3):245-248
The effect of layer thicknesses on the magnetic properties and mechanism of magnetization reversal in exchange-coupled NiFe/CoP film structures has been studied. The process of magnetization reversal was studied by analysis of the magnetic-induction and magneto-optical hysteresis loops. It is established that, as the thicknesses of layers in the NiFe/CoP film structure are increased, the system exhibits a transition from homogeneous magnetization reversal in the structure to exchange spring formation in the soft magnetic layer. 相似文献
4.
S. Anandakumar 《Thin solid films》2010,519(3):1020-1024
We present the observation of double shifted hysteresis loops in IrMn/NiFe bilayer structures. The bilayer structures were fabricated using high vacuum DC magnetron sputtering system. The hysteresis loops of the as deposited samples show the double shifted loops at NiFe layer thicknesses 5 nm and 6 nm, whereas the IrMn layer thickness was kept constant at 15 nm. The results were interpreted as the contribution of both positive and negative exchange bias fields. We suppose that this phenomenon is occurring due to the ferromagnetic (FM) layer exchange coupled with the antiferromagnetic (AFM) layer in two different magnetization directions. The ferromagnetic coupling of the interface spins in some regions of the film generates the hysteresis loop shift toward negative fields and antiferromagnetic coupling toward positive fields in the other regions. The double shifted hysteresis loops disappeared after magnetic field annealing of the samples above Neel temperature of the AFM layer. The X-ray diffraction patterns of the sample show the IrMn (111) crystalline growth necessary for the development of exchange bias field in this system. The correlation between the Magnetic Force Microscopy (MFM) domain structures of the as deposited sample and the magnetization reversal process of the double shifted hysteresis loops were discussed. The results suggest that the larger multidomain formation in the AFM layer with different magnetization directions was responsible for the positive and negative exchange bias fields in IrMn/NiFe bilayer samples. 相似文献
5.
The resonance magnetization dynamics in multilayer nanostructures exposed to transverse and longitudinal magnetic fields is
investigated with allowance for biquadratic exchange coupling between the magnetic moments of neighboring layers. It is found
that the crystallographic magnetic anisotropy leads to the appearance of a minimum on the field dependence of the resonance
frequency for the “acoustic” mode and the accompanying maximum in the magnetic susceptibility. 相似文献
6.
The effect of fringe-field coupling on the magnetization reversal process in submicrometer scale giant magnetoresistive pillars consisting of [NiFe/Cu]/sub 6/ has been investigated by means of current perpendicular to plane magnetoresistance measurements and numerical simulations. The parabolic and reversible magnetoresistance curves due to an opposite rotation of magnetization in neighboring NiFe layers were observed. To explain the field sensitivity of the pillars quantitatively, we have proposed a modified single-domain model, where the magnetic energy of the system is reconstructed using the result of the micromagnetic simulation of a magnetostatically coupled bilayer system. The calculated magnetoresistance curves are consistent with the experimental ones. From the calculated results, the amplitude of the saturation field is found to be proportional to the thickness of the ferromagnetic layer and inversely proportional to the square root of the nonmagnetic layer thickness. 相似文献
7.
Thin films of the zinc nickel ferrite, Zn0.7Ni0.3Fe2O4 (ZNFO), were deposited by the RF magnetron sputtering on a number of substrates, including (001) oriented single crystals of LaAlO3 (LAO) and SrTiO3 (STO), polycrystalline Pt/Si, and epitaxial films of BiFeO3 (BFO) and LaNiO3 (LNO). Except for the films on Pt/Si, the ZNFO films grown on other substrates were epitaxial and their magnetic properties were affected by the heteroepitaxy induced strains. Typically, the coercivity (Hc) was increased with the strain, i.e. Hc varied from 31 Oe for the 150 nm thick polycrystalline films grown on Pt/Si, to 55 Oe and 155 Oe for the 20 nm thick epitaxial films grown on BFO and LAO, respectively. The saturation magnetization of the epitaxial films was reduced accordingly to about 470 emu/cm3 from 986 emu/cm3 in the polycrystalline films. The all-oxide architecture allowed field-annealing to perform at the temperature above the Neel temperature of BFO (~ 370 °C), after which clear exchange bias was observed. 相似文献
8.
Hongchen ZHAO Guanghua YU Hong SIInstitute of Microelectronics Chinese Academy of Science Beijing ChinaDepartment of Materials Physics University of Science Technology Beijing Beijing ChinaCentral Iron Steel Research Institute Beijing China 《材料科学技术学报》2004,20(2):239-240
The structures of Ta/Ni_(81)Fe_(19) and Ni_(81)Fe_(19)/Ta are commonly used in magnetoresistance multilayers. It is found that the thickness of dead layer in Ta/Ni81Fe19/Ta was about 1.6±0.2 nm. X-ray photoelectron spectroscopy (XPS) was used to study the interfaces of Ta/Ni_(81)Fe_(19) and Ni_(81)Fe_(19)/Ta. The results show that there is a reaction at the two interfaces: 2Ta+Ni=NiTa_2, which caused the thinning of the effective NiFe layer. Furthermore, this reaction could also explain the phenomenon that the dead layer thickness of spin valves multilayers prepared by MBE is thinner than those prepared by magnetron sputtering. 相似文献
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11.
N. G. Chechenin P. N. Chernykh S. A. Dushenko I. O. Dzhun A. Y. Goikhman V. V. Rodionova 《Journal of Superconductivity and Novel Magnetism》2014,27(6):1547-1552
Two types of asymmetry in giant magnetoresistance (GMR) are observed which are not related to a training effect, but indicate different mechanisms of magnetization reversal of the pinned layer in spin-valve (SV) structures for ascending and descending field scans. GMR, exchange bias and coercivity in Si/Ta/NiFe/Cu/NiFe/IrMn/Ta SV-structures were investigated as functions of the thickness of the nonmagnetic spacer. The spacer thickness effects are discussed in correlation with layers microstructure and interfaces morphology variations. 相似文献
12.
Dual IBS (Ion Beam Sputtering) technique was used to fabricate NiO/NiFe bilayers. Various process conditions were examined to enhance the exchange field of the bilayer. Ion beam sputtering with an ion beam voltage above the threshold voltage and with the optimum ion beam current produced a fine-grained and smooth NiO film. This fine-grained surface followed by optimum etching exhibited an enhanced exchange field of 100 Oe. Growing NiO films were ion bombarded with a secondary ion-beam source having various beam voltages. The texture, surface roughness and grain size of the NiO films changed due to the ion bombardment; however, the grain size and/or surface roughness rather than texture was found to be responsible for controlling the exchange coupling. Furthermore, it was demonstrated that an optimum etching time of the NiO film prior to the depositing of NiFe for a large exchange field exists. With this optimum etching of the NiO film, surface segregated impurities could be eliminated without deteriorating the surface unnecessarily. Exchange fields and coercivities of the NiO/NiFe bilayers were measured with a MOKE (Magneto–Optic Kerr Effect) hysteresis looper and the surface properties of NiO films were examined with an AFM (Atomic Force Microscope) and an AES (Auger Electron Spectroscope). 相似文献
13.
The magnetic properties of EuS/Pb double layers (a ferromagnetic insulator on a superconducting metal) were investigated by means of 50 Hz hysteresis. The magnetic coupling between the two layers does not set in spontaneously. Two procedures for achieving magnetic coupling are described: first, by means of a d.c. magnetic field perpendicular to the film plane; secondly, with an a.c. field in the film plane. The coupled states are characterized by a slowing of the 50 Hz magnetization reversals. The degree of slow-down depends on the strength of the magnetic coupling. 相似文献
14.
O. E. Kovalenko 《Technical Physics Letters》2006,32(2):164-166
The influence of additional illumination on the photoconductivity of planar cadmium selenide/poly(ethylene terephthalate) (CdSe/PET) thin-film structures has been studied. The dependence of the photoconductivity of CdSe/PET samples on the wavelength and intensity of additional illumination is determined. The effect of the frequency of modulation of the exciting light on the spectra of optical quenching of photocurrent is considered. 相似文献
15.
采用磁控溅射方法在SiO2基体上制备了FePt/FeMn/NiFe/Ta多层膜样品,通过FeMn/NiFe双层膜交换偏置的变化研究了硬磁FePt不同磁化状态对反铁磁层FeMn的影响。实验表明,磁化了的L10相FePt能使FeMn在较薄的情况下(4.5nm)对NiFe产生比较强的交换偏置;而未被磁化的FePt对FeMn/NiFe交换偏置影响并不明显。认为更薄的反铁磁层对另外的铁磁层产生交换偏置是由于硬磁与反铁磁的界面交换耦合作用能增强反铁磁的稳定性。 相似文献
16.
The interfacial magnetism of NiO/NiFe bilayers with different NiFe layer thicknesses, produced by DC and RF magnetron sputtering, has been studied by magnetometry and X-ray magnetic circular dichroism (XMCD). In magnetic hysteresis loops, the exchange bias field was found to be inversely proportional to the NiFe layer thickness. The fit using the Meiklejohn and Bean model gives a coupling energy at the NiO/NiFe interface of approximately 0.027 mJ/m2. The analysis of the XMCD spectra of Fe and Ni, using the sum rules, shows a reduction of the effective spin magnetic moments in bilayers with NiFe thickness less than 4 nm. This reduction is attributed to hybridization of ferromagnetic and antiferromagnetic atoms d orbitals near the interface and/or formation of antiferromagnetic alloys due to atomic diffusion at the interfaces. 相似文献
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18.
Lin KW Kol PH Guo ZY Ouyang H van Lierop J 《Journal of nanoscience and nanotechnology》2007,7(1):265-271
We have investigated the structural and magnetic properties of ion-beam deposited polycrystalline NiFe (25 nm)/Fe-oxide (35 nm) bilayers. A film prepared with an assist beam O2 to Ar gas ratio of 0% during deposition had a bottom layer that consisted of pure b.c.c. Fe (a = 2.87 A) whereas films prepared with 19%O2/Ar and 35%O2/Ar had either Fe3O4 (a = 8.47 angstroms) or alpha-Fe2O3 (a = 5.04 angstroms, c = 13.86 angstroms) bottom layers, respectively. Cross-sectional transmission electron microscopy revealed a smooth interface between the top nano-columnar NiFe and bottom nano-columnar Fe-oxide layer for all films. At room temperature, the observed coercivity (Hc approximately 25 Oe) for a film prepared with 19% O2/Ar indicates the existence of a magnetically hard ferrimagnetic Fe3O4 phase that is enhancing the plain NiFe (Hc approximately 2 Oe) by way of exchange coupling. A significant amount of exchange bias is observed below 50 K, and at 10 K the size of exchange bias hysteresis loops shift increases with increasing oxygen in the films. Furthermore, the strongest exchange coupling (H(ex) approximately 135 Oe at 10 K) is with alpha-Fe2O3 (35% O2/Ar) as the bottom film layer. This indicates that the pure antiferromagnetic phases work better than ferrimagnetic phases when in contact with ferromagnetic NiFe. H(ex) (T) is well described by an effective AF domain wall energy that creates an exchange field with a (1 - T/T(crit)) temperature dependence. Hc (T) exhibits three distinct regimes of constant temperature that may indicate the existence of different AF spin populations that couple to the FM layer at different temperatures. 相似文献
19.
The sensitivity of CdSe/PETP thin-film structures with respect to the adsorption of ammonia, aqueous ammonia, and water vapor
from the gas phase at room temperature has been studied. The photoconductivity of the best samples exhibited reversible variations
within two orders of magnitude in response to the presence of ammonia vapor. The concentration of ammonia in the gas phase
can be measured in the interval from 0.25 to 25 vol %. 相似文献
20.
Interfacial effects on the magnetic profiles and interlayer exchange coupling of Co/CoSi multilayers
Density functional calculations are conducted to investigate the interlayer exchange coupling (IEC) between ferromagnetic Co slabs mediated by a CoSi spacer in Co/CoSi(001) multilayers with CsCl crystalline structure. For both sharp and mixed Co-Si interfaces we calculated the magnetic moment distribution and the energy stability for ferromagnetic (F) IEC and antiferromagnetic (AF) IEC between the Co slabs as function of the spacer thickness. We show that mixing near to the interface noticeably modifies the IEC to the extent that this can change from an oscillatory IEC as function of the spacer thickness to an exponentially decaying AF behavior. 相似文献