Elastic constant measurements on iron pnictide Ba(Fe 0.9 Co 0.1 ) 2 As with an optimal superconducting transition temperature of T SC = 23 K have been performed by the ultrasonic pulse echo method. The shear elastic C 66 associated strain ε x y reveals considerable softening 21% below 300 down to and becomes increasing in phase , while other constants ( 11 - 12 )/2 44 show no sign 80 4.2 K. electric quadrupole O v ' existing degenerate d z bands participates superconductivity present system.

Abstract Adiabatic demagnetization is currently gaining strong interest in searching for alternatives to 3 He-based refrigeration techniques achieving temperatures below 2 K. The main reasons that are the recent shortage and high price of rare helium isotope He. Here we report discovery a large magnetocaloric effect intermetallic compound YbPt Sn, which allows adiabatic cooling from K down 0.2 We demonstrate this with home-made refrigerator. Other materials, example, paramagnetic salts,...

We succeeded in synthesizing single crystals of the tetragonal antiferromagnet CeCoSi, which shows an anomalous pressure induced ordered phase (PIOP) with extraordinary high transition temperature T ∼ 40 K. In this paper, we present results magnetization, specific heat, and electrical resistivity at ambient using crystals. Magnetization curves up to H = 55 were also examined on a polycrystalline sample. From results, found new T0 12 K above antiferromagnetic TN 9.4 At T0, magnetization small...

Ultrasonic measurements have been carried out to investigate the critical dynamics of structural and superconducting transitions due degenerate orbital bands in iron pnictide compounds with formula Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$. The attenuation coefficient $α_{\mathrm{L}[110]}$ longitudinal ultrasonic wave for $(C_{11}+C_{12}+2C_{66})/2$ $x = 0.036$ reveals slowing down relaxation time around transition at $T_\mathrm{s} 65$ K, which is caused by ferro-type ordering quadrupole...

To clarify the origin of phase transition at TN = 10 K in trigonal chiral compound DyNi3Ga9, we performed ultrasonic measurements on single-crystalline samples. We found a significant elastic softening transverse modulus C66 toward TN. By analyzing data using strain susceptibility, positive sign quadrupole–quadrupole coupling constant for was obtained. These results strongly suggest that ferroquadrupolar ordering will be dominant Below TN, crystal symmetry lower from structure. Elastic below...

The rare-earth chiral compound ${\mathrm{DyNi}}_{3}{\mathrm{Ga}}_{9}$ with trigonal structure shows successive phase transitions at 10, 9, 5.5, and 2.5 K. We previously reported that the transverse elastic modulus ${C}_{66}$ exhibits significant softening toward ${T}_{\mathrm{Q}}=10$ K transition ${T}_{\mathrm{Q}}$ is ferroquadrupolar ordering due to quasidegenerate quartet under a crystal electric field (CEF). To investigate order parameter magnetic field-temperature diagrams of ordering,...

We performed high-magnetic-field magnetization, polarization, and ultrasonic measurements in ${\mathrm{Ba}}_{2}{\mathrm{CuGe}}_{2}{\mathrm{O}}_{7}$ to investigate field-induced multiferroic properties arising from a cross-correlation between electric dipoles quadrupoles addition magnetic dipoles. Magnetization $M$ shows saturation behavior above 20 T for several field directions, however, polarization ${P}_{c}$ exhibits an increase, elastic constants show softening T. Based on quantum states...

We calculate the RKKY interactions derived from ab initio calculations for intermetallic compound CeCoSi exhibiting hidden nonmagnetic order at T0 and examine instability towards possible multipole orders within random phase approximation. All 36 up to rank 5 are investigated, maximum susceptibility exhibits an antiferro with q = 0 multipoles of monopole I hexadecapole H0, yielding a charge imbalance f electrons two Ce atoms in unit cell. The obtained can explain some experiments.

We have performed surface acoustic wave (SAW) measurements to examine vacancies in a layer of boron-doped silicon wafer currently used semiconductor industry. A SAW with frequency fs = 517 MHz was optimally generated by an interdigital transducer comb gap \(w=2.5\) µm on piezoelectric ZnO film deposited the (001) surface. The propagating along [100] axis velocity \(v_{\text{s}}=4.967\) km/s is agreement Rayleigh wave, which shows ellipsoidal trajectory motion displacement components ux and...

We investigate the two-orbital periodic Anderson model, where local orbital fluctuations of f-electrons couple with a two-fold degenerate Jahn-Teller phonon, by using dynamical mean-field theory. It is found that heavy fermion state caused Coulomb interaction between U largely enhanced due to electron-phonon coupling g, in contrast case single-orbital model effects and g compete each other. In for large $U$ both lattice are enhanced, while charge (valence) spin suppressed. strong regime,...

We have investigated low-temperature properties at a longitudinal elastic constant C L[111] of boron-doped silicon crystal grown by floating zone (FZ) method. The softening depending on magnetic fields indicates that charge state V + vacancy orbital accommodating three electrons is stable. Appreciable anisotropy in the along [111] and [1\bar10] axes up to 10 T described terms quadrupole susceptibility for consisting Γ 8 quartet ground 6 doublet excited due spin–orbit interaction.

To investigate an influence of the quadrupole interaction to antiferromagnetic phase transition at ${T}_{\mathrm{N}}=5$ K in ${\mathrm{HoRu}}_{2}{\mathrm{Al}}_{10}$ under magnetic fields $H$, we measured specific heat, magnetization, and elastic moduli. From these measurements, clarified diagram for three principal axes. Under $H$ along $b$ axis, ${T}_{\mathrm{N}}$ decreases monotonically with increasing $H$. Although $a$ $c$ axes is also reduced boundary shows anomalous inflection point...

The low-temperature ultrasonic dispersion in the transverse ( C 11 - 12 )/2 mode of PrMg 3 with non-Kramers-doublet ground state has been investigated temperatures down to 20 mK. is caused by a thermally activated motions characterized an Arrhenius-type relaxation time τ=τ 0 exp E / k B T ) low activation energy, = 500 mK, and slow attempt time, τ =8.5×10 -10 s. coupling electric quadrupoles lattice vibrations leads vibronic dissipation. releases entropy ln 2 lowering temperature across...

We have investigated the quadrupole ordering of 4f-electrons and rattling motion guest rare-earth ions in clathrate compound Pr 3 Pd 20 Ge 6 using ultrasonic measurements. The elastic constants ( C 11 - 12 )/2 44 exhibit considerable softening at low temperatures. A minimum T Q1 = 0.25 K indicates antiferroquadrupole associated with a Γ doublet crystal-field ground state 8c site, while Q2 60 mK ferroquadrupole 5 triplet 4a site. phase depending on magnetic field direction shows highly...

The magnetic properties of CeMnSi with a tetragonal crystal structure were investigated for the first time using single crystals. exhibits an antiferromagnetic (AFM) ordering Mn-3d electrons at TN = 242 K, whereas Ce-4f remain paramagnetic down to lowest temperature following characteristic behaviors: moderately enhanced Sommerfeld coefficient, steep decrease in electrical resistivity low temperatures, and almost temperature-independent susceptibility temperatures despite Curie–Weiss...

We have carried out ultrasonic measurements of a boron-doped silicon ingot grown by the Czochralski method in order to determine quadrupole-strain interaction constant vacancy orbital. The low-temperature softening elastic \(C_{44}\) shows remarkable variation depending on positions ingot, which reflects distribution concentration \(N\) ingot. An infrared laser scattering tomograph was employed measure density and size voids wafers determining \(N_{\text{cons}}\) consumed void formation....

We study the ternary clathrate ${\mathrm{Pr}}_{3}{\mathrm{Pd}}_{20}{\mathrm{Si}}_{6}$ in specific heat and ac susceptibility measurements on a high-quality single crystal, distinguishing antiferromagnetic antiferroquadrupolar ordering, as well hitherto unknown magnetic low-temperature transition. The shows direct involvement of nuclear spin degrees freedom which is supported by our calculation hyperfine level scheme without adjustable parameters. is, therefore, one rare materials where...

The magnetic properties of LaMnSi with a nonsymmorphic tetragonal structure were investigated using single crystals for the first time. exhibits an antiferromagnetic (AFM) ordering Mn-3d electrons at TN = 293 K. Since magnetization along [001] direction decreases steeply on cooling below TN, AFM ordered moment is parallel to direction. We also found that electrical resistivity shows small upturn indicating energy gap partially opened. mechanism formation not ascribed superzone gap, as often...

We have carried out low-temperature ultrasonic measurements using shear-mode ultrasound to clarify the quantum state of a vacancy orbital in boron-doped silicon grown by floating zone (FZ) method. The elastic constants \((C_{11}-C_{12})/2\) and \(C_{44}\) transverse mode exhibit considerable softening below 2 5 K down base temperature 30 mK, respectively. constant measured three modes \((k_{x},u_{y})\), \((k_{z},u_{x})\), \((k_{x},u_{z})\) shows different magnetic field dependences among...