اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMagnetic, Transport, and Phonon Properties of the Trivalent Eu Metallic Compound EuBe13
107
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Magnetic susceptibility, specific heat, and electrical resistivity measurements have been performed on single-crystal EuBe13 in the temperature range between 2 and 300 K to investigate its phonon property and the valence state of the Eu ion. The obtained temperature dependence of the magnetic susceptibility curves obey a typical Van Vleck susceptibility for Eu3+ with a nonmagnetic ground state in the entire measured temperature range. In the case of the specific heat, we observed the coexistence of Debye and Einstein phonon modes with characteristic Debye and Einstein temperatures of ~ 835 K and ~167 K, respectively, which are in good agreement with those previously reported for other isostructural MBe13 compounds (M = rare earths and actinides). The temperature dependence of the resistivity for EuBe13 shows an unusual T-cubed like dependence at low temperatures, as also observed for the nonmagnetic isostructural compound LaBe13, which can be reproduced well by calculations based on electron--phonon scattering using the estimated Debye temperature and Einstein temperature. We also summarized the relationship between the Eu-valence state and the free distance between the Eu ion and the first-nearest-neighbor atoms in several Eu-based cubic compounds, and argued that EuBe13 takes the Eu3+ state despite its larger free distance than other Eu3+ compounds.
قيم البحث
اقرأ أيضاً
We have found that CeCd$_{3}$P$_{3}$ crystallizes into a hexagonal ScAl$_{3}$C$_{3}$-type structure. The optical, transport and magnetic properties of CeCd$_{3}$P$_{3}$ were investigated by measuring the diffuse reflectance, electrical resistivity an
d magnetization. CeCd$_{3}$P$_{3}$ is a semiconductor with the fundamental band gap of approximately 0.75 eV. The 4$f$ electrons of Ce$^{3+}$ ions are well localized but do not show long range order down to 0.48 K, presumably due to the geometrical frustration of Ce atoms. The magnetic ordering temperature is possibly lower than that of isostructural CeZn$_{3}$P$_{3}$ (0.75 K). Because several $f$-electron compounds with the ScAl$_{3}$C$_{3}$-type structure are quantum spin systems, CeCd$_{3}$P$_{3}$ may be a candidate of quantum spin liquid. On the other hand, the relatively large band gap compared to approximately 0.4 eV in CeZn$_{3}$P$_{3}$, would not be intimate with the observation of photoinduced Kondo effect, providing a potentially new range of applications of devices based on the Kondo effect.
In this work, we combined magnetization, pressure dependent electrical resistivity, heat-capacity, 63Cu Nuclear Magnetic Resonance (NMR) and X-ray resonant magnetic scattering experiments to investigate the physical properties of the intermetallic Ce
CuBi2 compound. Our single crystals show an antiferromagnetic ordering at TN ~ 16 K and the magnetic properties indicate that this compound is an Ising antiferromagnet. In particular, the low temperature magnetization data revealed a spin-flop transition at T = 5 K when magnetic fields about 5.5 T are applied along the c-axis. Moreover, the X-ray magnetic diffraction data below TN revealed a commensurate antiferromagnetic structure with propagation wavevector (0 0 1/2) with the Ce^3+ moments oriented along the c-axis. Furthermore, our heat capacity, pressure dependent resistivity and temperature dependent 63Cu NMR data suggest that CeCuBi2 exhibits a weak heavy fermion behavior with strongly localized Ce^3+ 4f electrons. We thus discuss a scenario taking into account the anisotropic magnetic interaction between the Ce^3+ ions along with the tetragonal crystalline electric field effects in CeCuBi2.
In this work we report the physical properties of the new intermetallic compound TbRhIn5 investigated by means of temperature dependent magnetic susceptibility, electrical resistivity, heat-capacity and resonant x-ray magnetic diffraction experiments
. TbRhIn5 is an intermetallic compound that orders antiferromagnetically at TN = 45.5 K, the highest ordering temperature among the existing RRhIn5 (1-1-5, R = rare earth) materials. This result is in contrast to what is expected from a de Gennes scaling along the RRhIn5 series. The X-ray resonant diffraction data below TN reveal a commensurate antiferromagnetic (AFM) structure with a propagation vector (1/2 0 1/2) and the Tb moments oriented along the c-axis. Strong (over two order of magnitude) dipolar enhancements of the magnetic Bragg peaks were observed at both Tb absorption edges LII and LIII, indicating a fairly high polarization of the Tb 5d levels. Using a mean field model including an isotropic first-neighbors exchange interaction J(R-R) and the tetragonal crystalline electrical field (CEF), we were able to fit our experimental data and to explain the direction of the ordered Tb-moments and the enhanced TN of this compound. The evolution of the magnetic properties along the RRhIn5 series and its relation to CEF effects for a given rare-earth is discussed.
We have measured the electric resistivity, magnetoresistance, magnetic susceptibility and magnetization of the new Kondo-lattice compound Ce3Pd4Ge4. The electrical resistivity exhibits a rapid drop at temperatures below 6 K, while the magnetic suscep
tibility does not show any corresponding anomaly at that temperature. This phenomenon is similar to that of Ce3Pd20Ge6 which shows quadrupolar interation. We suggest that there is the possibility of quadrupolar interaction in the orthorhombic 4f-electron system Ce3Pd4Ge4. In addition, it is realized that the spin-dependent scattering effect is responsible for the magnetotransport.
The structural, electronic, and magnetic properties of bulk GdCu (CsCl-type) are investigated using spin density functional theory, where highly localized $4f$ orbitals are treated within LDA+$U$ and GGA+$U$ methods. The calculated magnetic ground st
ate of GdCu using collinear as well as spin spiral calculations exhibits a C-type antiferromagnetic configuration representing a spin spiral propagation vector $mathbf{Q}=frac{2pi}{a}(frac{1}{2},frac{1}{2},0)$. The parameters of the effective Heisenberg Hamiltonian are evaluated from a self-consistent electronic structure and are used to determine the magnetic transition temperature. The estimated N{e}el temperature of the cubic GdCu using GGA+$U$ and LDA+$U$ density functionals within the mean field and random phase approximations are in good agreement with the experimentally measured values. In particular, the theoretical understanding of the experimentally observed core Gd $4f$ levels shifting in photoemission spectroscopy experiments is investigated in detail. By employing the self-consistent constrained random-phase approximation we determined the strength of the effective Coulomb interaction (Hubbard $U$) between localized $4f$ electrons. We find that, the shift of Gd-$4f$ states in GdCu with respect to bulk Gd within DFT+$U$ is sensitive to choice of lattice parameter. The calculations for $4f$-level shifts using DFT+$U$ methods as well as Hubbard-1 approximation are not consistent with the experimental findings.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
