共查询到18条相似文献,搜索用时 156 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
实验研究了石榴石磁泡薄膜中不同脉冲宽度下产生的硬磁畴的动态特性.结果表明:由零偏场下产生的枝状畴收缩而成的哑铃畴均逆时针转动,与产生枝状畴时所用的脉冲偏场的脉冲宽度无关.而固定直流偏场下由软畴段硬化而成的哑铃畴的转动状态,则与所用的硬化脉冲偏场的脉冲宽度有关.低脉冲宽度下硬化成的哑铃畴均逆时针转动,随硬化脉冲宽度的升高,出现混合转动向顺时针转动的过渡.由此揭示了直流偏场和脉冲偏场在石榴石磁泡薄膜中形成正、负垂直布洛赫线的作用.
关键词:
磁畴
磁泡
垂直布洛赫线 相似文献
10.
在八个(111)面磁泡膜上,观察了施加面内(in-plane)磁场后在不同晶轴方向上条状畴的消失过程,测量了条畴消失场Hs*和磁畴消失场Hk*与面内磁场的方向的关系。本文计及立方磁晶各向异性,完善了面内磁场中条畴的稳定性理论。用该理论定性地解释了实验结果的主要特点。导出了Hs*与立方各向异性及面内场方向的两种近似的理论关系,它们分别适用于面内场方向靠近和不十分靠近〈110〉晶轴的情形。它们和实验结果是大致符合的。在〈110〉晶轴上,理论关系具有下列简单的形式:Hk*<110>=Hs*<110>=Hk{1+(k1/2Ku)-[al/h(4πMs/Hk)2]2/3},此式与实验结果符合得相当好。
关键词: 相似文献
11.
12.
实验研究了温度对液相外延石榴石磁泡薄膜中条状普通硬磁畴壁内的垂直布洛赫线(VBL)链解体临界面内磁场区间的影响。发现存在一对特征温度T(1)0 和 T(2)0(前者比后者略低但均高于室温),在从室温到T(2)0的每个温度T下,使VBL逐渐消失的面内磁场Hip都分布于一个与T有关的区间[Hip(1)(T), Hip(2)(T)]内,称为临界面内磁场区间:Hip<Hip(1)(T)时,VBL链保持不变;Hip(1)(T)< Hip < Hip(2)(T)时,随着Hip的增加,越来越多的VBL消失;Hip > Hip(2)(T)时,所有VBL都消失。Hip(1)(T),Hip(2)(T)及Hip(2)(T)-Hip(1)(T)均随T的升高而下降,前二者分别于T(1)0 和 T(2)0降为零。比值Hip(2)(T)/Hip(1)(T)随T的升高而升高,在低温段(包括室温)升高缓慢且约为21/2,在T(1)0附近急剧升高且至T(1)0时趋于∞。对以上结果做了理论分析。
关键词: 相似文献
13.
ANNIHILATION OF VERTICAL-BLOCH-LINE CHAINS IN THE WALLS OF THE SECOND KIND OF DUMBBELL DOMAINS SUBJECTED TO JOINT STATIC BIAS FIELD AND IN-PLANE FIELD 下载免费PDF全文
Experiments were statistically carried out on the behavior of vertical-Bloch-line(VBL) chains in the walls of the second kind of dumbbell domains (IIDs) is garnet bubble films subjected to joint action of static bias field Hb and in-plane field Hip. The curves of the four critical in-plane fields, (Hip)IID-ID (Hip)IID-OHB (Hip)IID-SB and H'ip vs Hb were measured and explained. In particular, in terms of two series of IID photos, a new experimental manifestation of the unknown "number effect" of VBL chains was found. 相似文献
14.
15.
INFLUENCE OF IN-PLANE FIELD ON THE STABILITY OF VERTICAL BLOCH LINE CHAINS IN HARD DOMAINS OF GARNET BUBBLE FILMS 总被引:4,自引:0,他引:4 下载免费PDF全文
The stability of vertical Bloch line (VBL) chains was statistically studied for all three types of bard domains in garnet bubble films subjected to an in-plane field Hip. With a set of integrate data taken from seven bubble samples and with two typical figures of a sample, four main features of the behavior of VBL chains subjected to Hip were summarized. 相似文献
16.
M. E. Palistrant I. D. Chebotar V. A. Ursu 《Journal of Experimental and Theoretical Physics》2009,109(2):227-236
A theory describing the magnetic properties of a two-band superconductor with a varying charge carrier density is constructed.
The upper critical field H
c2(ab) parallel to the ab plane and field H
c2(c) parallel to the c axis are determined in the entire temperature range 0 < T < T
c
. A considerable increase in upper critical field H
c2(ab) as compared to H
c2(c) because of strong anisotropy of the system is detected. Anisotropy of coefficient γ
H
= H
c2(ab) / H
c2(c) is obtained as a function of temperature for pure MgB2 and as a function of the chemical potential in the case when Mg and B atoms are replaced with other chemical elements. A
correlation between the variation in the superconducting transition temperature upon an increase in the chemical potential
and critical magnetic fields H
c2(ab) and H
c2(c) is observed. The effect of doping on magnetic anisotropy is also determined. 相似文献
17.
B V B Sarkissian A K Grover G Balakrishnan Ravi Kumar P L Paulose R Vijayaraghavan V Sankaranarayanan C K Subramanian 《Pramana》1992,38(6):641-667
The results of experimental studies on hysteresis in magnetization, thermomagnetic history effects, anomalous variations in
magnetic hysteresis curves and the decay rates of magnetization obtained under different thermomagnetic histories in specimens
of conventional and high temperature superconductors are presented. The Bean’s critical state model is considered adequate
to explain magnetic behaviour in conventional hard superconductors. The similarity in the general features of the results
of different experiments on specimens of the two families of superconductors underscores the efficacy of the said model to
understand some aspects of the macroscopic magnetic response of high temperature superconductors as well. For instance, the
isothermal magnetization hysteresis loop which comprises of magnetization curves along forward (−H
max to +H
max) and reverse (+H
max to −H
max) paths define an envelop within which all isothermal magnetization data along different thermomagnetic histories lie. There
exist inequality relationship between various field values identified asH
peak,H
I,H
II etc. in isothermal magnetization hysteresis as well as magnetic relaxation data. The entire field span of an isothermal magnetization
hysteresis data set can be considered to comprise of three parts corresponding to (M
rem(H)−M
FC(H)+M
ZFC(H)) being equal to, less than or greater than zero, whereM
rem(H) are the remanent magnetization values obtained on reducing field to zero after having the specimen in different applied
field (H) values. There are, however some situations amongst thermomagnetic history effects in specimens which show incomplete flux
trapping on field cooling, where the critical state model has been found inadequate. 相似文献
18.
E. A. Shapoval 《JETP Letters》1999,69(8):577-583
The lower critical field H
c1
cyl
(T) of a superconducting cylinder with radius r
0∼ξ(T)≪λ(T) is found on the basis of the Ginzburg-Landau theory with various boundary conditions. These results together with the well-known
results for the upper critical field are used to construct phase diagrams in terms of the field versus the reduced radius
r
0∼ξ(T) variables. The jump in the average magnetization at H
c1
cyl
(T) is calculated as a function of the reduced radius.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 8, 537–542 (25 April 1999) 相似文献