اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدTransport and Magnetic properties of Fe1/3VSe2
107
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Electrical conductivity, thermopower and magnetic properties of Fe-intercalated Fe0.33VSe2 has been reported between 4.2K - 300K. We observe a first order transition in the resistivity of the sintered pellets around 160K on cooling. The electronic properties including the transitional hysteresis in the resistance anomaly (from 80K-160K) are found to be very sensitive to the structural details of the samples, which were prepared in different annealing conditions. The thermopower results on the sintered pellets are reported between 10K - 300K. The magnetic measurements between 2K - 300K and up to 14 Tesla field show the absence of any magnetic ordering in Fe0.33VSe2. The magnetic moment per Fe -atom at room temperature (between 1.4 to 1.7 Bohr Magneton) is much lower than in previously reported anti-ferromagnetic FeV2Se4. Furthermore, the Curie constant shows a rapid and continuous reduction and combined with the high field magnetization result at 2K suggests a rapid decrease in the paramagnetic moments on cooling to low temperatures and the absence of any magnetic order in Fe0.33VSe2 at low temperatures.
قيم البحث
اقرأ أيضاً
Nanostructured La0.67Ca0.33MnO3 (NS-LCMO) was formed by pulsed-laser deposition on the surface of porous Al2O3. The resistance peak temperature (Tp) of the NS-LCMO increases with increasing average thickness of the films, while their Curie temperatur
es (Tc) remain unchanged. The coercive field of the samples increases with decreasing film thickness and its temperature dependence can be well described by Hc(T) = Hc(0)[1-(T/TB)1/2]. A large magnetoresistance and strong memory effect were observed for the NS-LCMO. The results are discussed in terms of the size effect, Coulomb blockade and magnetic tunneling effect. This work also demonstrates a new way to get nanostructured manganites.
Here we report the evolution of structural, magnetic and transport properties in MnBi$_{2-x}$Sb$_x$Te$_4$ (0$leq x leq$2) single crystals. MnSb$_2$Te$_4$, isostructural to MnBi$_2$Te$_4$, has the lattice parameters of textit{a}=4.2445(3)$AA$ and text
it{c}=40.869(5)$AA$, respectively. With increasing Sb content in MnBi$_{2-x}$Sb$_x$Te$_4$, the textit{a}-lattice decreases linearly following the Vegards law while the textit{c}-lattice shows little compositional dependence. The textit{a}-lattice contraction occurs by reducing Mn-Te-Mn bond angle while Mn-Te bond length remains nearly constant. The anisotropic magnetic properties suggest an antiferromagnetic order below T$_N$=19,K for MnSb$_2$Te$_4$ with the magnetic moments aligned along the crystallographic textit{c}-axis. The antiferromagnetic ordering temperature slightly decreases from 24,K for MnBi$_2$Te$_4$ to 19,K for MnSb$_2$Te$_4$. More dramatic change was observed for the critical magnetic fields required for the spin-flop transition and moment saturation. With increasing Sb content, both critical fields decrease and in MnSb$_2$Te$_4$ a small field of 3,kOe is enough to saturate the moment. In high magnetic fields, the saturation moment shows significant suppression from 3.56$mu_B$/Mn for MnBi$_2$Te$_4$ to 1.57$mu_B$/Mn for MnSb$_2$Te$_4$. Data analyses suggest that both the interlayer magnetic interaction and single ion anisotropy decrease with increasing Sb content. The partial substitution of Bi by Sb also dramatically affects the transport properties. A crossover from n-type to p-type conducting behavior is observed around x=0.63. Our results show close correlation between structural, magnetic and transport properties in MnBi$_{2-x}$Sb$_x$Te$_4$ and that partial substitution of Bi by Sb is an effective approach to fine tuning both the magnetism and transport properties of MnBi$_{2-x}$Sb$_x$Te$_4$.
The observation of quantized anomalous Hall conductance in the forced ferromagnetic state of MnBi2Te4 thin flakes has attracted much attentions. However, strong magnetic field is needed to fully polarize the magnetic moments due to the large antiferr
omagnetic interlayer exchange coupling. Here, we reported the magnetic and electrical transport properties of the magnetic van der Waals MnBi2Te4(Bi2Te3)n (n=1,2) single crystals, in which the interlayer antiferromagnetic exchange coupling is greatly suppressed with the increase of the separation layers Bi2Te3. MnBi4Te7 and MnBi6Te10 show weak antiferromagnetic transition at 12.3 and 10.5 K, respectively. The ferromagnetic hysteresis was observed at low temperature for both of the crystals, which is quite crucial for realizing the quantum anomalous Hall effect without external magnetic field. Our work indicates that MnBi2Te4(Bi2Te3)n (n=1,2) provide ideal platforms to investigate the rich topological phases with going to their 2D limits.
Room temperature ferromagnetism was observed in n-type Fe-doped In2O3 thin films deposited on c-cut sapphire substrates by pulsed laser deposition. Structure, magnetism, composition, and transport studies indicated that Fe occupied the In sites of th
e In2O3 lattice rather than formed any metallic Fe or other magnetic impurity phases. Magnetic moments of films were proved to be intrinsic and showed to have a strong dependence on the carrier densities which depended on the Fe concentration and its valance state as well as oxygen pressure.
The effect of gold capping on magnetic and transport properties of optimally doped manganite thin films is studied. An extraordinary suppression of conductivity and magnetic properties occurs in epitaxial (001) La_0.67Sr_0.33MnO_3 (LSMO) films grown
on SrTiO_3 upon deposition of 2 nm of Au: in the case of ultrathin films of LSMO (4 nm thick) the resistivity increases by four orders of magnitude while the Curie temperature decreases by 180 K. Zero-field 55Mn nuclear magnetic resonance reveals a significant reduction of ferromagnetic double-exchange mechanism in manganite films upon the gold capping. We find evidence for the formation of a 1.9-nm thick magnetic dead-layer at the Au/LSMO interface, associated with the creation of interfacial non double-exchange insulating phases.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
