共查询到20条相似文献,搜索用时 31 毫秒
1.
A. V. Svalov G. V. Kurlyandskaya H. Hammer P. A. Savin O. I. Tutynina 《Technical Physics》2004,49(7):868-871
The saturation magnetization, the perpendicular and rotational anisotropy constants, and the coercitivity of Ni75Fe16Cu5Mo4 thin magnetic films produced by rf sputtering are measured in the initial state and after annealing. A relation between the presence of perpendicular anisotropy and the “transcritical” state in the films is established. It is shown that, after additional thermal treatment, the magnetic softness of the films can be improved. 相似文献
2.
Compressed
Pr0.5Ca0.5MnO3
films (250 nm) deposited on LaAlO3 have
been studied by Electron Spin Resonance technique under high
frequency and high magnetic field. We show evidences for the
presence of a ferromagnetic phase (FM) embedded in the
charge-order phase (CO), in form of thin layers which size
depends on the strength and orientation of the magnetic field
(parallel or perpendicular to the substrate plane). This FM
phase presents an easy plane magnetic anisotropy with an
anisotropy constant 100 times bigger than typical bulk values.
When the magnetic field is applied perpendicular to the
substrate plane, the FM phase is strongly coupled to the CO
phase whereas for the parallel orientation it keeps an
independent ferromagnetic resonance even when the CO phase
becomes antiferromagnetic. 相似文献
3.
Magnetic anisotropies of 20 nm epitaxial film of palladium–iron alloy Pd0.92Fe0.08 grown on the (001) MgO substrate were studied. Ferromagnetic resonance (FMR) spectroscopy and vibrating sample magnetometry (VSM) were exploited to determine magnetic parameters of the film. It was found that the synthesized film reveals cubic anisotropy with tetragonal distortion. The simulated magnetic hysteresis loops, obtained utilizing the magnetic anisotropy constants taken from the FMR spectra analysis, agree well with those measured by VSM. 相似文献
4.
E. N. Sheftel’ S. V. Komogortsev R. S. Iskhakov P. K. Sidorenko L. A. Chekanova N. S. Perov A. N. Ivanov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(10):1449-1451
The magnetic properties (magnetization curve, ferromagnetic resonance spectrum) of nanocrystalline Fe79Zr10N11 films obtained by RF magnetron sputtering with subsequent annealing were studied experimentally, along with the fundamental
magnetic constants of these films (saturation magnetization M
S, local magnetic anisotropy energy K, and the exchange coupling constant A). The magnetic properties are discussed within the random magnetic model, which determines the correlation of the magnetic
properties with the fundamental magnetic constants and nanostructure parameters (grain size, magnetic anisotropy, and correlation
radius R
C). The exchange correlation length 2R
L
for the film magnetic microstructure was determined by correlation magnetometry. 相似文献
5.
A phenomenological theory for polarization flop in spiral multiferroic TbMnO<Subscript>3</Subscript>
A phenomenological Landau theory has been used to explain magnetic field-driven polarization flop in TbMnO 3. The Néel wall-like magnetic structure in spiral multiferroics induces a space-dependent internal magnetic field which exerts a torque on spins to rotate bc-spiral to ab-spiral. The external magnetic field is argued to be competing with easy axis anisotropy and the system stabilizes when anisotropy is minimum. With the help of Landau free energy with DM magnetoelectric coupling and a general ansatz for magnetization, the phenomenon of polarization flop has been explained. Relation between Tflop and critical magnetic field has been established and found to be in good agreement with the experiment. This could be an indication that anisotropy of the system is temperature- and magnetic field-dependent. 相似文献
6.
A. D. Balaev N. B. Ivanova N. V. Kazak S. G. Ovchinnikov V. V. Rudenko V. M. Sosnin 《Physics of the Solid State》2003,45(2):287-291
Temperature and field dependences of the magnetization of VBO3 and CrBO3 single crystals with the magnetic field applied parallel and perpendicular to the (111) basal plane were measured. VBO3 was found to have a considerable uniaxial anisotropy with a field Ha≈6.25 T. CrBO3 was shown to exhibit not only uniaxial but also hexagonal anisotropy. The experimental anisotropy constants were estimated, and their temperature dependences are presented. 相似文献
7.
A. V. Semirov D. A. Bukreev A. A. Moiseev V. A. Lukshina E. G. Volkova S. O. Volchkov 《Russian Physics Journal》2011,54(5):612-618
The influence of the thermal treatment type on the temperature dependences of the magnetoimpedance of nanocrystalline Fe73.5Si16.5B6Nb3Cu1 alloy strips is investigated. The main mechanisms determining the temperature behavior of the magnetoimpedance of strips
with induced magnetic anisotropy having various special features are established. The prospects for application of the alloy
strips nanocrystallized in the presence of a magnetic field as sensitive elements of temperature sensors and special magnetic
field detectors are demonstrated. 相似文献
8.
S. N. Zinenko A. A. Murakhovski L. P. Ol’khovik Z. I. Sizova E. V. Shurinova A. S. Kamzin 《Journal of Experimental and Theoretical Physics》2003,96(5):945-952
The equation of the magnetization of a hexagonal crystal is derived for the first time for an arbitrary orientation of the external magnetic field relative to the crystallographic c axis. In order to clarify the magnetization mechanism for a real ensemble of small particles in the framework of the given problem, surface anisotropy (which is significant for nanosize objects) was taken into account along with crystalline magnetic anisotropy and anisotropy in the particle shape. Model computer experiments prove that the magnetization curves for nanocrystals oriented in a polar angle range of 65–90° exhibit an anomaly in the form of a jump, indicating a first-order spin-reorientation phase transition. This explains a larger steepness of the experimental curve reconstructed taking into account the interaction between particles as compared to the theoretical dependence obtained by Stoner and Wohlfarth [IEEE Trans. Magn. MAG 27 (4), 3469 (1991)]. An analysis of variation of the characteristic anisotropy surface and its cross section with increasing ratio |K2|/K1 of the crystalline magnetic anisotropy constants upon a transition from a macroscopic to a nanoscopic crystal shows that surface anisotropy leads to a change in the magnetic structure. As a result, an additional easy magnetization direction emerges in the basal plane apart from the easiest magnetization direction (along the c axis). The direction of hard magnetization emerges from the basal plane, the angle of its orientation relative to the c axis being a function of the ratio | K2|/K1. 相似文献
9.
The role of material microstructure in the magnetic
anisotropy of real nanostructures has been studied by the comparison of the
magnetic behavior of arrays of amorphous and polycrystalline
CoxSi1-x lines. From the experimental measurements of angular
dependences of remanences parallel and perpendicular to the applied field we
determine the angular dispersion of effective local easy axis of anisotropy.
We have proved that amorphous lines have a dispersion of effective
anisotropy axis much smaller than the polycrystalline samples. As a
consequence, amorphous lines have a better defined magnetic behaviour,
pointing the interest of the fabrication of nanostructures made of amorphous
materials. 相似文献
10.
G.?A.?Petrakovski? M.?A.?Popov A.?D.?Balaev K.?A.?Sablina O.?A.?Bayukov D.?A.?Velikanov A.?M.?Vorotynov A.?F.?Bovina A.?D.?Vasil’ev M.?Boehm 《Physics of the Solid State》2009,51(9):1853-1858
Single crystals of Pb2Fe2Ge2O9 have been grown. They were subjected to X-ray diffraction, magnetic, neutron diffraction, Mössbauer and spin resonance studies. It has been established that Pb2Fe2Ge2O9 is a weak ferromagnet with a Néel temperature T N = 46 K, and the exchange and spin-flop transition fields have been estimated. It has been demonstrated that the weak ferromagnetic moment is actually the result of the single-ion anisotropy axes for the magnetic moments of different magnetic sublattices being not collinear. 相似文献
11.
Daniel Grant Michael Ryan Amlan Biswas 《The European Physical Journal B - Condensed Matter and Complex Systems》2018,91(9):197
The perovskite material (La0.4Pr0.6)0.67Ca0.33MnO3 (LPCMO) has complex electronic and magnetic behavior based on phase competition between ferromagnetic metallic (FMM) and insulating phases with similar free energies. Experimental evidence has indicated that in-plane stress anisotropy influences these phases and can affect electronic and magnetic properties. Here we investigate the roles that both stress and shape anisotropies may play in controlling the coercive field of the material. LPCMO thin films of various thicknesses (20, 25, and 30 nm) were deposited on (110) NdGaO3 (NGO) substrates using pulsed laser deposition and the coercive fields were measured. Photolithography was then used to fabricate microstructured arrays of LPCMO on the NGO substrates for each of the films. The coercive fields of these arrays of LPCMO were compared to the behavior of the corresponding unpatterned LPCMO thin films across a range of temperatures. Microstructure arrays for the thicker (25 and 30 nm) films showed a substantial increase in the coercive field after forming the arrays, whereas a thinner film (20 nm) showed almost no change in the coercive field. Stress anisotropy continues to play a dominant role in the behavior of LPCMO thin films and dimensionality of the magnetic domains also influences the results. The films show 2D behavior when film thickness approaches the size of the critical radius for single-to-multidomain transitions. Making thicker films allows for 3D behavior and a role for shape anisotropy to influence the coercive fields. 相似文献
12.
P. D. Kim I. A. Turpanov S. V. Stolyar R. S. Iskhakov V. I. Yushkov A. Ya. Beten’kova L. A. Li E. V. Bondareva T. N. Isaeva M. M. Karpenko 《Technical Physics》2004,49(4):431-434
The crystal structure and hysteretic magnetic properties of equiatomic single-crystal CoPt films applied on MgO substrates
by magnetron sputtering, as well as modification of these properties by thermal annealing, are studied. Heat-treated films
of thickness in the range 2<d≤16 nm exhibit perpendicular magnetic anisotropy. A correlation between the crystalline anisotropy constant of the CoPt films
and the order parameter of the LI0 superstructure in these alloys is found. The effect of a single-crystalline MgO substrate on the structure and magnetic properties
of equiatomic CoPt films is revealed. 相似文献
13.
F. B. Mushenok A. I. Dmitriev M. V. Kirman S. M. Aldoshin N. A. Sanina R. B. Morgunov 《Physics of the Solid State》2010,52(10):2135-2141
Ordered arrays of nanowires of the photochromic antiferromagnet SpFeMn(C2O4)3 (where Sp is 1-{(1′,3′,3′-trimethyl-6-nitro-5′-chlorospiro[2H-1-benzopyran-2,2′-indolin]-8-yl)methyl}pyridinium) have been fabricated in anodized aluminum oxide pores with diameters of
20 and 200 nm. It has been revealed that the growth of the spin-glass phase with noncollinear ordering of spins in nanowires
is suppressed in favor of the uniaxial antiferromagnetic phase. A decrease in the nanowire diameter leads to an increase in
the anisotropy of the magnetic resonance spectra. This is associated with the magnetocrystalline anisotropy that considerably
exceeds the anisotropy of the nanowire shape. 相似文献
14.
G.?A.?Petrakovski? L.?N.?Bezmaternykh D.?A.?Velikanov M.?S.?Malokeev O.?A.?Bayukov A.?M.?Vorotynov R.?Szymchak 《Physics of the Solid State》2009,51(12):2486-2491
High-quality CuCoAlBO5 single crystals have been grown, and their crystal structure, magnetic susceptibility, and magnetization have been studied.
It has been established that the CuCoAlBO5 compound is an uncompensated antiferromagnet or ferrimagnet with a small magnetic moment and the magnetic ordering temperature
T
N = 28 K. A model has been proposed for the magnetic structure. A strong anisotropy of the magnetic properties has been revealed. 相似文献
15.
I. S. Tereshina G. A. Beskorovainaya N. Yu. Pankratov V. V. Zubenko I. V. Telegina V. N. Verbetsky A. A. Salamova 《Physics of the Solid State》2003,45(1):104-108
The structure and magnetic properties of RFe11TiN compounds (R=Gd or Lu) containing nitrogen are investigated. Magnetic measurements are performed on a magnetometer in magnetic fields up to 100 kOe in the temperature range from 4.2 to 750 K with the use of RFe11TiN single crystals, RFe11TiN powders placed in a ceramic cell, and samples oriented in an external magnetic field. It is found that the nitridation leads to an increase in the Curie temperature and the saturation magnetization. The samples studied are uniaxial over the entire temperature range of magnetic ordering. The magnetic anisotropy decreases upon nitridation. It is demonstrated that, within the local anisotropy model, the decrease in the magnetic anisotropy constant K1 can be explained by the redistribution of the electron density in the vicinity of the crystallographic positions occupied by iron atoms. 相似文献
16.
G. Kh. Panova A. A. Shikov N. A. Chernoplekov A. A. Zhokhov A. N. Maljuk C. T. Lin 《Physics of the Solid State》2003,45(12):2237-2241
The anisotropy in the superconducting properties of single-crystal Nd1.85Ce0.15CuO4 was studied from measurements of the heat capacity within the temperature interval 2–40 K in zero magnetic field and in a magnetic field of 8 T. We report on the first observation of heat capacity jumps occurring at the superconducting transition for various magnetic field orientations with respect to the crystallographic axes and on a strong anisotropy of the magnetic contribution to heat capacity in magnetic fields oriented in the a-b plane and perpendicular to it. These measurements yielded the anisotropy in the electronic heat capacity coefficient γn(H) and in the superconducting transition temperature Tc(H). The angular dependence of the Sommerfeld coefficient γn in the a-b plane observed in a magnetic field of 8 T exhibits four-lobe symmetry and zero gap direction of the order parameter. A comparison of the results obtained on the Nd1.85Ce0.15CuO4 single crystal with the data available for La1.85Sr0.15CuO4 permits one to conclude that the mechanisms of superconductivity in the electron-and hole-doped superconductors are similar. 相似文献
17.
A. M. Balagurov I. A. Bobrikov V. Yu. Pomjakushin E. V. Pomjakushina D. V. Sheptyakov I. O. Troyanchuk 《JETP Letters》2011,93(5):263-268
The magnetic and crystal structures of the Pr0.5Sr0.5CoO3 metallic ferromagnet have been studied by the neutron diffraction technique. It is demonstrated that below 150 K, the compound
is mesoscopically separated into two crystalline phases with different spatial symmetries and with different directions of
the magnetic anisotropy. The phase separation exists down to 1.5 K, and at temperatures below 90 K, the low-symmetry phase
occupies about 80% of the sample volume. The main structural difference between the phases is the configuration of oxygen
atoms around praseodymium and, to a certain extent, around cobalt. The ferromagnetic structure with the magnetic moment lying
in the basal plane of the structure (μCo ≈ 1.7 μ
B
at 1.5 K) arises at 234 K, whereas the component directed along the long axis of the unit cell appears at 130 K. The formation
of the new structural phase and change in the orientation of the magnetic moment give rise to the anomalies of the physical
and magnetic characteristics of this compound observed earlier at temperatures about 120 K. 相似文献
18.
E. E. Shalyguina I. Škorvánek P. Švec V. A. Mel’nikov N. M. Abrosimova 《Journal of Experimental and Theoretical Physics》2004,99(3):544-551
Inverted hysteresis loops were observed for the first time in the near-surface layers of heterogeneous (nanocrystalline/amorphous) Fe81Nb7B12 alloys. In particular, a negative residual magnetization is observed when a positive magnetic field applied in the sample plane is decreased to zero. The inverted hysteresis is qualitatively explained within the framework of a two-phase model, according to which the heterogeneous alloys contain two dissimilar phases exhibiting uniaxial magnetic anisotropy and featuring antiferromagnetic exchange interaction. 相似文献
19.
D. J. Goossens 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,78(3):305-309
The nature of the anisotropy in magnetic systems which show isotropic Heisenberg
exchange is crucial in determining their magnetic properties. This is
particularly true in low-dimensional systems in which the very existence
of long-range order depends on the anisotropy.
The honeycomb lattice MnPS3 system has been studied as an example of
a magnetically quasi-two-dimensional system of unusual symmetry.
In this paper the effect of the dipole-dipole interaction in
MnPS3 on the magnetic ordering is explored through modelling.
It is found that the dipolar anisotropy can explain the spin directions both in zero field
and above the spin flop phase transition, but it is important that real
rather than idealised atomic coordinates are used; this latter
consideration is significant because in performing theoretical
calculations, it may sometimes be assumed that small deviations away
from the ideal can be ignored, but in truth they determine key
aspects of the behaviour. 相似文献
20.
The magnetic resonance properties of [(CoP)soft/NiP/(CoP)hard/NiP]n multilayer films with the properties of magnetic springs have been experimentally studied. It has been found that the deposition of a NiP nonmagnetic amorphous layer on a (CoP)soft magnetic layer induces the appearance of perpendicular interface anisotropy. The increase in the number of blocks n in the multilayer structure leads to the appearance of the third absorption peak, which is explained by the formation of a noncollinear three-sublattice magnetic structure. 相似文献