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A neutron powder diffraction experiment has been performed on the quasicrystal approximant ${\mathrm{Au}}_{72}{\mathrm{Al}}_{14}{\mathrm{Tb}}_{14}$, a body-centered-cubic crystal of icosahedral spin clusters. The long-range antiferromagnetic order was confirmed at the transition temperature ${T}_{\mathrm{N}}=10.4$ K. The magnetic structure consists of noncoplanar whirling spins on the icosahedral clusters, arranged in an antiferroic manner. A simple icosahedral spin-cluster model with uniaxial anisotropy accounts well the whirling spin order as well as the in-field metamagnetic transition, indicating that the icosahedral symmetry is essential.

In an ideal classical pyrochlore antiferromagnet without perturbations, an infinite degeneracy in a ground state leads to the absence of magnetic order and a spin-glass transition. Here we present ${\mathrm{Na}}_{3}\mathrm{Mn}{({\mathrm{CO}}_{3})}_{2}\mathrm{Cl}$ as a new candidate compound where classical spins are coupled antiferromagnetically on the pyrochlore lattice and report its structural and magnetic properties. The temperature dependences of the magnetic susceptibility and heat capacity and the magnetization curve are consistent with those of an $S=5/2$ pyrochlore lattice antiferromagnet with nearest-neighbor interactions of 2 K. Neither an apparent signature of a spin-glass transition nor magnetic order is detected in magnetization and heat capacity measurements or powder neutron diffraction experiments. On the other hand, antiferromagnetic short-range order of the nearest neighbors is evidenced by the $Q$ dependence of the diffuse scattering which develops around $0.85\phantom{\rule{0.16em}{0ex}}{\AA{}}^{\ensuremath{-}1}$. A high degeneracy near the ground state in ${\mathrm{Na}}_{3}\mathrm{Mn}{({\mathrm{CO}}_{3})}_{2}\mathrm{Cl}$ is supported by the magnetic entropy, estimated as almost $4\phantom{\rule{0.16em}{0ex}}\mathrm{J}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}{\mathrm{mol}}^{\ensuremath{-}1}$ at 0.5 K.

We measured magnetization, specific heat, electron spin resonance, neutron diffraction, and inelastic neutron scattering of ${\mathrm{CrVMoO}}_{7}$ powder. An antiferromagnetically ordered state appears below ${T}_{\mathrm{N}}=26.5\ifmmode\pm\else\textpm\fi{}0.8$ K. We consider that the probable spin model for ${\mathrm{CrVMoO}}_{7}$ is an interacting antiferromagnetic spin-$\frac{3}{2}$ dimer model. We evaluated the intradimer interaction $J$ to be $25\ifmmode\pm\else\textpm\fi{}1$ K and the effective interdimer interaction ${J}_{\mathrm{eff}}$ to be $8.8\ifmmode\pm\else\textpm\fi{}1$ K. ${\mathrm{CrVMoO}}_{7}$ is a rare spin dimer compound that shows an antiferromagnetically ordered state at atmospheric pressure and zero magnetic field. The magnitude of ordered moments is $0.73(2){\ensuremath{\mu}}_{\mathrm{B}}$. It is much smaller than a classical value $\ensuremath{\sim}3{\ensuremath{\mu}}_{\mathrm{B}}$. Longitudinal-mode magnetic excitations may be observable in single crystalline ${\mathrm{CrVMoO}}_{7}$.

Small angle neutron scattering measurements have been performed to study the thermodynamic stability of skyrmion-lattice phases in Cu$_2$OSeO$_3$. We found that the two distinct skyrmion-lattice phases [SkX(1) and SkX(2) phases] can be stabilized through different thermal histories; by cooling from the paramagnetic phase under finite magnetic field, the SkX(2) phase is selected. On the other hand, the 30$^{\circ}$-rotated SkX(1) phase becomes dominant by heating the sample from the ordered conical phase under finite field. This difference in stabilization is surprisingly similar to the irreversibility observed in spin glasses. The zero-field cooling results in the co-existence of the two phases. It is further found that once one of the skyrmion-lattice phases is formed, it is hardly destabilized. This indicates unusual thermal stability of the two skyrmion-lattice phases originating from an unexpectedly large energy barrier between them., 9 pages, 10 figures

The magnetic structure of the double perovskite compound ${\mathrm{Sr}}_{2}{\mathrm{CuTeO}}_{6}$ was determined from neutron powder diffraction data. This material is magnetically described as an $S=1/2$ quasi-two-dimensional square-lattice Heisenberg model with antiferromagnetic nearest-neighbor and next-nearest-neighbor interactions. ${\mathrm{Sr}}_{2}{\mathrm{CuTeO}}_{6}$ undergoes a magnetic phase transition at ${T}_{\mathrm{N}}\ensuremath{\simeq}29$ K. The spin structure below ${T}_{\mathrm{N}}$ is N\'eel antiferromagnetic on the square lattice, which means that the nearest-neighbor interaction $({J}_{1})$ is stronger than the next-nearest-neighbor interaction $({J}_{2})$, in contrast to other isostructural compounds such as ${\mathrm{Ba}}_{2}{\mathrm{CuWO}}_{6}$ and ${\mathrm{Sr}}_{2}{\mathrm{CuWO}}_{6}$, for which $|{J}_{1}|l|{J}_{2}|$ is realized.

We investigated the iron-based ladder compounds (Ba,$\mathrm{Cs}){\mathrm{Fe}}_{2}{\mathrm{Se}}_{3}$. Their parent compounds ${\mathrm{BaFe}}_{2}{\mathrm{Se}}_{3}$ and ${\mathrm{CsFe}}_{2}{\mathrm{Se}}_{3}$ have different space groups, formal valences of Fe, and magnetic structures. Electrical resistivity, specific heat, magnetic susceptibility, x-ray diffraction, and powder neutron diffraction measurements were conducted to obtain a temperature and composition phase diagram of this system. Block magnetism observed in ${\mathrm{BaFe}}_{2}{\mathrm{Se}}_{3}$ is drastically suppressed with Cs doping. In contrast, stripe magnetism observed in ${\mathrm{CsFe}}_{2}{\mathrm{Se}}_{3}$ is not so fragile against Ba doping. A new type of magnetic structure appears in intermediate compositions, which is similar to stripe magnetism of ${\mathrm{CsFe}}_{2}{\mathrm{Se}}_{3}$, but interladder spin configuration is different. Intermediate compounds show insulating behavior, nevertheless a finite $T$-linear contribution in specific heat was obtained at low temperatures.

High intensity pulsed neutron scattering reveals a new set of magnetic excitations in the pinwheel valence bond solid state of the distorted kagome lattice antiferromagnet Rb$_2$Cu$_3$SnF$_{12}$. The polarization of the dominant dispersive modes (2 meV $

Magnetic diffuse scattering in the Zn-Mg-Ho icosahedral quasicrystal has been studied by neutron scattering over a wide $\mathit{Q}$ range using a single-quasicrystalline sample. It was found that the diffuse scattering obeys the icosahedral symmetry, and appears as satellite peaks of the intense nuclear Bragg reflections. The diffuse-scattering patterns were successfully accounted for by assuming short-range spin correlations in a six-dimensional hypercubic crystal with a magnetic modulation vector $\mathit{q}=(\frac{3}{4},0,0,\frac{1}{2},\frac{3}{4},\frac{1}{2}{)}_{{\mathit{a}}^{*}}.$ A possible origin for the six-dimensional spin correlations is discussed.

The origin of the nonmagnetic phase transition in PrTi${}_{2}$Al${}_{20}$, reported earlier in a macroscopic study, has been asserted microscopically using elastic and inelastic neutron scattering techniques. It has been shown spectroscopically that the crystalline-electric-field ground state is a nonmagnetic ${\ensuremath{\Gamma}}_{3}$ doublet, whereas the excited states are two triplets (${\ensuremath{\Gamma}}_{4}$ and ${\ensuremath{\Gamma}}_{5}$) and a singlet (${\ensuremath{\Gamma}}_{1}$). The diffraction experiment under external magnetic field shows that the nonmagnetic transition is indeed ferroquadrupolar ordering, which takes place as a consequence of cooperative removal of the ground-state-doublet degeneracy. It is therefore concluded that PrTi${}_{2}$Al${}_{20}$ is another rare example of Pr compounds exhibiting nonmagnetic quadrupolar order.

A quasiperiodic intermediate-valence (IV) system is realized in an icosahedral Au-Al-Yb quasicrystal. X-ray absorption spectroscopy near the Yb ${L}_{3}$ edge indicates that quasiperiodically arranged Yb ions assume a mean valence of 2.61, between a divalent state ($4{f}^{14}$, $J=0$) and a trivalent one ($4{f}^{13}$, $J=7/2$). Magnetization measurements demonstrate that the $4f$ holes in this quasicrystal have a localized character. The magnetic susceptibility shows a Curie-Weiss behavior above $\ensuremath{\sim}100$ K with an effective magnetic moment of 3.81${\ensuremath{\mu}}_{\mathrm{B}}$ per Yb. Moreover, a crystalline approximant to this quasicrystal is an IV compound. We propose a heterogeneous IV model for the quasicrystal, whereas the crystalline approximant is most likely a homogeneous IV system. At temperatures below $\ensuremath{\sim}10$ K, specific heat and magnetization measurements reveal non-Fermi-liquid behavior in both the quasicrystal and its crystalline approximant without either doping, pressure, or field tuning.

Structural and electronic properties of the Fe-based spin-ladder compound CsFe${}_{2}$Se${}_{3}$ was investigated by means of resistivity, susceptibility, specific heat, M\"ossbauer, and neutron diffraction measurements. Despite the single-site nature in a mixed-valence state, the ground state is a magnetic insulator characterized by a charge gap \ensuremath{\sim}0.34 eV and an antiferromagnetic transition temperature 175 K. The magnetic structure was stripelike, with magnetic moments of 1.77(6)${\ensuremath{\mu}}_{\mathrm{B}}$ coupled ferromagnetically (antiferromagnetically) along the rung (leg) direction. Both the insulating behavior and stripelike ordering can be understood by assuming extra carriers delocalized on the rung. Our findings reveal that CsFe${}_{2}$Se${}_{3}$ is an appealing compound with the stripelike magnetic structure in an insulating state among Fe-based compounds, and provide significant supplemental insight into the magnetism of Fe-based superconductors.

Magnetism in the insulating BaFe${}_{2}$Se${}_{3}$ was examined through susceptibility, specific heat, resistivity, and neutron diffraction measurements. After formation of a short-range magnetic correlation, a long-range ordering was observed below ${T}_{\mathrm{N}}\ensuremath{\sim}255$ K. The transition is obscured by bulk properties. Magnetic moments ($\ensuremath{\parallel}a$) are arranged to form a Fe${}_{4}$ ferromagnetic unit, and each Fe${}_{4}$ stacks antiferromagnetically. This block magnetism is of the third type among magnetic structures of ferrous materials. The magnetic ordering drives unusually large distortion via magnetoelastic coupling.

Inelastic neutron scattering (INS) experiments have been performed on the Cu${}_{3}$ triangular molecular nanomagnet using powder samples. In the medium resolution INS experiment, two peaks were observed at $\ensuremath{\hbar}\ensuremath{\omega}=0.5$ and 0.6 meV, whereas an additional excitation peak was detected at very low energy $\ensuremath{\hbar}\ensuremath{\omega}=0.1$ meV in the higher resolution experiment. A model Hamiltonian and its optimum interaction parameters were determined from the observed peak position, width, and intensity. A key ingredient of the model Hamiltonian is Dzyaloshinsky-Moriya interactions as suggested in the earlier reports, which is now directly evidenced by the observation of the 0.1-meV peak, corresponding indeed to a splitting of ground-state quartet into two doublets. Temperature dependences of integrated intensity of the 0.5- and 0.6-meV peaks are well reproduced by the Boltzmann distribution function up to 10 K, above which a small deviation was detected. Nevertheless, the inelastic peaks were visible even at very high temperatures as 50 K, indicating extraordinary weak coupling between spins and lattice vibrations (or any other perturbations) compared to the other known molecular nanomagnets.

Using quasielastic neutron scattering (QENS), we have investigated a self-diffusive behavior of Li${}^{+}$ ions for both $^{7}\mathrm{Li}$Mn${}_{2}$O${}_{4}$ and $^{7}\mathrm{Li}$${}_{1.1}$Mn${}_{1.9}$O${}_{4}$ spinels. In addition, we have carried out elastic and inelastic neutron scattering measurements using the same samples, to study the interrelationship between Li${}^{+}$ self-diffusion, magnetism, and charge distribution in the lattice. From the QENS results, the self-diffusion of Li${}^{+}$ was observable above 280 K, and a self-diffusion coefficient (${D}_{s}^{\mathrm{Li}}$) for $^{7}\mathrm{Li}$Mn${}_{2}$O${}_{4}$ was estimated as $~{10}^{\ensuremath{-}8}$ cm${}^{2}$/s at 400 K. ${D}_{s}^{\mathrm{Li}}$ for $^{7}\mathrm{Li}$${}_{1.1}$Mn${}_{1.9}$O${}_{4}$ was comparable to that for $^{7}\mathrm{Li}$Mn${}_{2}$O${}_{4}$. Furthermore, combining with the results of elastic and inelastic measurements, it was found that $^{7}\mathrm{Li}$${}_{1.1}$Mn${}_{1.9}$O${}_{4}$ undergoes a transition from a low-temperature ($T$) short-range charge-ordered (SRCO) phase to a high-$T$ charge-disordered (CDO) phase at 280 K. The structure of the SRCO was determined as a hexagon, because the formation of hexagon spin clusters was deduced from a magnetic diffuse scattering at low $T$. Assuming the presence of the SRCO-CDO transition at 280 K, both the anomaly of the diffusive behavior at 280 K and the local lattice distortion below 280 K are reasonably explained, despite the absence of long-range CO for $^{7}\mathrm{Li}$${}_{1.1}$Mn${}_{1.9}$O${}_{4}$.

Structure and magnetic properties of the rhombohedral-structure compound ${\text{Co}}_{2}{(\text{OH})}_{3}\text{Br}$, a member of the geometrically frustrated series of the compounds ${M}_{2}{(\text{OH})}_{3}X$ where the magnetic ions form a deformed pyrochlore lattice, were studied using dc and ac magnetic susceptibilities, heat-capacity, neutron powder-diffraction, and muon-spin-rotation/-relaxation $(\ensuremath{\mu}\text{SR})$ measurements. The structure of ${\text{Co}}_{2}{(\text{OH})}_{3}\text{Br}$ is featured by alternatively stacked layers of perfect kagome-lattice planes and triangular-lattice planes with a 10% distortion along the stacking direction (the $c$ axis). Despite a very small difference in the distortion [0.42% larger in ${\text{Co}}_{2}{(\text{OH})}_{3}\text{Br}$], ${\text{Co}}_{2}{(\text{OH})}_{3}\text{Br}$ was found to show contrasting antiferromagnetism that is strikingly different from the previously reported ferromagnetic ${\text{Co}}_{2}{(\text{OH})}_{3}\text{Cl}$. Successive antiferromagnetic transition was observed at ${T}_{\text{N}1}=6.2\text{ }\text{K}$ and ${T}_{\text{N}2}=4.8\text{ }\text{K}$, respectively. The antiferromagnetic ground state is metastable and an intermediate magnetic phase was induced by applying a relatively low magnetic field of $H\ensuremath{\sim}5\text{ }\text{kOe}$. When the field was further increased above $H\ensuremath{\sim}20\text{ }\text{kOe}$ spin reorientation occurred to form a configuration similar to ferromagnetic ${\text{Co}}_{2}{(\text{OH})}_{3}\text{Cl}$. The successive antiferromagnetic transitions in zero field were found to occur with propagation vector of ${\mathbit{k}}_{1}=(0\text{ }\ensuremath{-}1/2\text{ }1/2)$ at ${T}_{\text{N}1}$ and an additional ${\mathbit{k}}_{2}=(0\text{ }0\text{ }3/2)$ at ${T}_{\text{N}2}$. Refinement of the neutron powder-diffraction patterns revealed an unconventional multi-$\mathbit{k}$ and noncoplanar spin structure for the antiferromagnetic phases. Multiple measurements, in particular, the $\ensuremath{\mu}\text{SR}$ study, consistently demonstrated magnetic coupling at high temperatures, and persistent fluctuations well below the ${T}_{\text{N}}$. This work presents a unique system to investigate the orbital effect and the critical role of lattice distortion in geometric frustration, and provides a single material system to study multiple phase transitions and competing exchange interactions.

The spin dynamics in single crystal, electron-doped Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} has been investigated by inelastic neutron scattering over the full range from undoped to the overdoped regime. We observe damped magnetic fluctuations in the normal state of the optimally doped compound (x=0.06) that share a remarkable similarity with those in the paramagnetic state of the parent compound (x=0). In the overdoped superconducting compound (x=0.14), magnetic excitations show a gaplike behavior, possibly related to a topological change in the hole Fermi surface (Lifshitz transition) while the imaginary part of the spin susceptibility {chi}' prominently resembles that of the overdoped cuprates. For the heavily overdoped, nonsuperconducting compound (x=0.24) the magnetic scattering disappears, which could be attributed to the absence of a hole Fermi-surface pocket observed by photoemission.

Ryota Akiyama,1 Yutaka Ikedo,2,* Martin Mansson,3 Tatsuo Goko,4 Jun Sugiyama,2 Daniel Andreica,5 Alex Amato,6 Kittiwit Matan,1 and Taku J. Sato1,† 1Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106, Japan 2Toyota Central Research and Development Laboratories Inc., Nagakute, Aichi 480-1192, Japan 3Laboratory for Neutron Scattering, ETH Zurich and Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland 4TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 5Faculty of Physics, Babes-Bolyai University, 3400 Cluj-Napoca, Romania 6Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland

A general approach is outlined to predict the chemical compositions of solute nanoclusters embedded in materials with nearly free electrons. Based on the experimental results of the two-dimensional angular correlation of positron annihilation radiation and the corresponding theoretical calculations, we show that the Fermi surface (FS)--Brillouin zone interaction is a key to understand the chemical composition realized in solute nanoclusters because the presence of FS necks at zone boundaries causes a reduction in electron energy due to the band-gap effect.

K. Kamazawa,1 Despina Louca,1,* R. Morinaga,2 T. J. Sato,2 Q. Huang,3 J. R. D. Copley,3 and Y. Qiu3,4 1Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA 2Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan 3NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA 4Dept. of Materials Science and Engineering, University of Maryland, College Park, Maryland, 20742, USA Received 2 June 2008; published 13 August 2008

Using neutron scattering techniques, we have investigated spin wave excitations in noncollinear ferrimagnetic spinels $\mathrm{Mn}{B}_{2}{\mathrm{O}}_{4}$ $(B=\mathrm{Mn},\mathrm{V})$ with ${e}_{g}$ and ${t}_{2g}$ orbital degeneracies, respectively, that lead to tetragonal distortions along opposite directions. Linear spin wave analysis of the excitations yields spatially inhomogeneous nearest neighbor interactions in both tetragonal spinels. We find the ratio ${J}^{c}∕{J}^{ab}\ensuremath{\approx}\ensuremath{-}0.06(4)$ for ${\mathrm{Mn}}_{3}{\mathrm{O}}_{4}$ $(cga=b)$ and $\ensuremath{\approx}0.3(1)$ for $\mathrm{Mn}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$ $(cla=b)$. Resulting exchange couplings of ${\mathrm{Mn}}_{3}{\mathrm{O}}_{4}$ can be qualitatively explained in terms of possible overlaps of ${t}_{2g}$ and ${e}_{g}$ electrons of ${\mathrm{Mn}}^{2+}$ and ${\mathrm{Mn}}^{3+}$ ions. On the other hand, those of $\mathrm{Mn}{\mathrm{V}}_{2}{\mathrm{O}}_{4}$, in particular, the strong ${J}^{c}$, seem to contradict with the antiferro-orbital state of ${\mathrm{V}}^{3+}$ $({t}_{2g}^{2})$ ions that was proposed by a recent synchrotron x-ray study [T. Suzuki et al., Phys. Rev. Lett. 98, 127203 (2007)]. Theoretical implications to the orbital physics are also discussed.

Neutron scattering experiments have been performed on the ternary rare-earth diborocarbide ${\mathrm{Ce}}^{11}{\mathrm{B}}_{2}{\mathrm{C}}_{2}$. The powder-diffraction experiment confirms formation of a long-range magnetic order at ${T}_{\mathrm{N}}=7.3\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, where a sinusoidally modulated structure is realized with the modulation vector $\mathbit{q}=[0.167(3),0.167(3),0.114(3)]$. Inelastic excitation spectra in the paramagnetic phase comprise significantly broad quasielastic and inelastic peaks centered at $\ensuremath{\hbar}\ensuremath{\omega}\ensuremath{\approx}0$, 8, and $65\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$. Crystalline-electric-field (CEF) analysis satisfactorily reproduces the observed spectra, confirming their CEF origin. The broadness of the quasielastic peak indicates strong spin fluctuations due to coupling between localized $4f$ spins and conduction electrons in the paramagnetic phase. A prominent feature is suppression of the quasielastic fluctuations, and concomitant growth of a sharp inelastic peak in a low-energy region below ${T}_{\mathrm{N}}$. This suggests dissociation of the conduction and localized $4f$ electrons on ordering, and contrasts the presently observed incommensurate phase with spin-density-wave order frequently seen in heavy fermion compounds, such as ${\mathrm{Ce}}_{x}{\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ru}}_{2}{\mathrm{Si}}_{2}$.

Undoped ${\mathrm{CoS}}_{2}$ is an isotropic itinerant ferromagnet with a continuous or nearly continuous phase transition at ${T}_{\mathrm{C}}=122\mathrm{K}.$ In the doped ${\mathrm{CoS}}_{1.9}{\mathrm{Se}}_{0.1}$ system, the Curie temperature is lowered to ${T}_{\mathrm{C}}=90\mathrm{K},$ and the transition becomes clearly first order in nature. In particular we find a discontinuous evolution of the spin dynamics as well as strong time relaxation in the ferromagnetic Bragg intensity and small-angle neutron scattering in the vicinity of the ferromagnetic transition. In the ordered state the long-wavelength spin excitations were found to be conventional ferromagnetic spin waves with negligible spin-wave gap $(l0.04\mathrm{meV}),$ indicating that this system is also an excellent isotropic (soft) ferromagnet. In a wide temperature range up to ${0.9T}_{\mathrm{C}},$ the spin-wave stiffness $D(T)$ follows the prediction of the two-magnon interaction theory, $D(T)=D(0)(1\ensuremath{-}{\mathrm{AT}}^{5/2}),$ with $D(0)=131.7\ifmmode\pm\else\textpm\fi{}2.8\mathrm{meV}{\AA{}}^{2}.$ The stiffness, however, does not collapse as $\stackrel{\ensuremath{\rightarrow}}{T}{T}_{\mathrm{C}}$ from below. Instead a quasielastic central peak abruptly develops in the excitation spectrum, quite similar to results found in the colossal magnetoresistance oxides such as ${(\mathrm{L}\mathrm{a}\ensuremath{-}\mathrm{C}\mathrm{a})\mathrm{MnO}}_{3}.$

Superconducting properties of single-crystalline $\mathrm{Ca}({\mathrm{Al}}_{0.5},{\mathrm{Si}}_{0.5}{)}_{2},$ which is isostructural to ${\mathrm{MgB}}_{2},$ were studied by measurements of electrical resistivity, Hall coefficient, and magnetization. $\mathrm{Ca}({\mathrm{Al}}_{0.5},{\mathrm{Si}}_{0.5}{)}_{2}$ is a type-II superconductor with a carrier density of $8.6\ifmmode\times\else\texttimes\fi{}{10}^{26}{\mathrm{e}\mathrm{l}\mathrm{e}\mathrm{c}\mathrm{t}\mathrm{r}\mathrm{o}\mathrm{n}\mathrm{s}/\mathrm{m}}^{3}$ at 290 K. The lower critical field ${H}_{C1}$ has a parabolic temperature dependence typical for conventional superconductors. The upper critical field ${(H}_{C2})$ anisotropy ratio has a temperature-independent value of 2.3. The Ginzburg-Landau (GL) parameter \ensuremath{\kappa}(0) is equal to 12 and 5.2 in the ab-plane and c-axis directions, respectively. The anisotropy of the critical fields can be well described by the anisotropic GL theory.