Physical Sciences Division

By using the detection system of the near-horizontal cosmic-ray radiography originally developed for probing inner structure of volcanic mountains, a measurement was conducted to probe the inner structure and its time-dependent change of the blast furnace for iron-making. Precise determination (±5 cm) of the thickness of brick used for both base-plate and side-wall was made in 45 days; a crucial information to predict a life-time of the furnace. Also, the local density of iron-rich part was determined in ±0.2 g/cm2 in 45 days; static structure as well as time-dependent behavior can be monitored for the iron-rich part of the furnace during operation. (Communicated by Kazuhiko NISHIJIMA, M.J.A.)

Muon-spin-rotation and -relaxation studies have been performed on ${(\mathrm{C}{\mathrm{H}}_{3})}_{2}\mathrm{C}\mathrm{H}\mathrm{N}{\mathrm{H}}_{3}\mathrm{Cu}{({\mathrm{Cl}}_{x}{\mathrm{Br}}_{1\ensuremath{-}x})}_{3}$ with $x=0.85$ and 0.95, which are solid solutions of the two isomorphic spin-gap systems ${(\mathrm{C}{\mathrm{H}}_{3})}_{2}\mathrm{C}\mathrm{H}\mathrm{N}{\mathrm{H}}_{3}\mathrm{Cu}{\mathrm{Cl}}_{3}$ and ${(\mathrm{C}{\mathrm{H}}_{3})}_{2}\mathrm{C}\mathrm{H}\mathrm{N}{\mathrm{H}}_{3}\mathrm{Cu}{\mathrm{Br}}_{3}$ with different spin gaps. The sample with $x=0.85$ showed a clear muon spin rotation under zero-field below ${T}_{N}=11.65\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, indicating the existence of a long-range antiferromagnetic order. A critical exponent of the hyperfine field was obtained to be $\ensuremath{\beta}=0.33$, which agrees with 3D-Ising model. In the other sample with $x=0.95$, an anomalous enhancement of the muon spin relaxation was observed at very low temperatures indicating a critical slowing down due to a magnetic instability of the ground state.

The 31P-NMR (nuclear magnetic resonance) measurements of the filled skutterudite SmRu4P12 have been carried out in several applied magnetic fields. The line width of the 31P-NMR spectrum rapidly increases below the metal-insulator transition temperature TMI, which indicates the appearance of an internal field below the temperature. Though no distinct anomaly was observed below TMI in low fields, a complicated structure was observed between the Neel temperature TN and TMI (TN < TMI) above 70 kOe. The spin-lattice relaxation rate 1/T1 is almost independent of temperature above TMI, and rapidly decreases below TMI. The 1/T1 in low fields decreases monotonously, whereas the strong suppression of 1/T1 occurs between TN and TMI above 70 kOe. The structure of the spectra and the suppression of 1/T1 become apparent with increasing field.

Zero-field muon-spin-relaxation (ZF-{\boldmath $\mu$}SR) measurements were carried out down to 80 mK on the randomness bond system Tl$_{1-x}$K$_x$CuCl$_3$ with $x$ = 0.44. Time spectra are well fitted by the stretched exponential function $\exp (-\lambda t)^{\beta}$. The muon spin relaxation rate $\lambda$ increases rapidly with decreasing temperature, and $\beta$ tends to 0.5 at 80 mK. The divergent increase of $\lambda$ suggests the critical slowing down of the frequency of the Cu-3{\it d} spin fluctuations toward a spin frozen state below 80 mK, and the root-exponential-like behavior of the time spectrum indicates that the origin of the relaxation is possibly the spatially-fixed fluctuating dilute moments.

The 31P-NMR (nuclear magnetic resonance) and muSR (muon spin relaxation) measurements on the filled skutterudite system SmFe4P12 have been carried out. The temperature T dependence of the 31P-NMR spectra indicates the existence of the crystalline electric field effect splitting of the Sm3+$ (J = 5/2) multiplet into a ground state and an excited state of about 70 K. The spin-lattice relaxation rate 1/T1 shows the typical behavior of the Kondo system, i.e., 1/T1 is nearly T independent above 30 K, and varies in proportion to T (the Korringa behavior, 1/T1 \propto T) between 7.5 K and 30 K. The T dependence deviated from the Korringa behavior below 7 K, which is independent of T in the applied magnetic field of 1 kOe, and suppressed strongly in higher fields. The behavior is explained as 1/T1is determined by ferromagnetic fluctuations of the uncovered Sm3+ magnetic moments by conduction electrons. The muSR measurements in zero field show the appearance of a static internal field associated with the ferromagnetic order below 1.6 K.

The sound velocity Vs of La2−xSrxCuO4 around x = 0.220 has been measured in magnetic fields up to 12 T. The increase of Vs by applying magnetic fields was observed in case of x = 0.220, and resembles the enhancement of the increase of Vs observed in the concentration of x around 0.115. The magnetic field dependence of Vs in x = 0.220 scales with that observed in x = 0.120. This result strongly suggests that the observed magnetic field effect on the sound velocity has the same origin with that in x ∼ 0.115.

Abstract Spin excitation of an ilmenite FeTiO 3 powder sample is measured by time-of-flight inelastic neutron scattering. The dynamic magnetic pair-density function D M ( r, E ) is obtained from the dynamic magnetic structure factor S M ( Q, E ) by the Fourier transformation. The real space spin dynamics exhibit magnon mode transitions in the spin–spin correlation with increasing energy from no-phase-shift to π-phase-shift. The mode transition is well reproduced by a simulation using the reciprocal space magnon dispersions. This analysis provides a novel opportunity to study the local spin dynamics of various magnetic systems.

Positive muon spin-relaxation (<em>µ</em>⁺SR) measurements on a spin-ladder material Na₂Co₂(C₂O₄)₃(H₂O)₂ are reported. We find that the relaxation rate, <em>λ</em>, under a longitudinal field of 3950 Oe increases with decreasing temperature, <em>T</em>, and is a maximum at <em>T</em>_peak ≃ 18 K. Below <em>T</em>_peak, <em>λ</em> decreases with decreasing <em>T</em>. This finding implies the observation of a spin gap formation by <em>µ</em>⁺SR technique. The approach of the exponent <em>β</em> in the relaxation function to 0.5 with decreasing <em>T </em> suggests a freezing of dilute moments. Below about 5 K, we observe a sinusoidal oscillation in the time spectrum in zero applied field, which indicates an onset of long-range magnetic order. All these observations give microscopic evidence that the spin-ladder material is close to a quantum critical point.

The 31 P nuclear magnetic resonance ( 31 P-NMR) and muon spin relaxation (µSR) of the filled skutterudite compound SmRu 4 P 12 have been carried out. The line width of the 31 P-NMR spectrum rapidly increases below the metal–insulator transition temperature T MI but not below the Néel temperature T N . The temperature dependence of the spin–lattice relaxation rate shows a successive anomaly at T MI and T N . The µSR measurements indicate that a static internal field appears below T MI , which means that the ordering below T MI is a magnetic ordering with the time reversal symmetry breakdown. These results support a scenario that a magnetic octupolar ordering occurs below T MI in SmRu 4 P 12 .

Background: Parkinson's disease (PD) is the most typical neurological disorder associated with aging in humans. Since PD has much to do with the medical field, most research studies focus on the biological, chemical, and medical aspects of the investigations, in addition to epidemiological studies, drug intervention studies, and much more. The lack of studies using scanning tunneling microscopy (STM) to investigate the electron transfer properties of DNA in PD opens up a new opportunity to look at electron transfer, which is fundamental to understanding the biological processes of the damage-repair mechanism of DNA in this disease, from a physical perspective. Hence, this systematic review was conducted to identify the methods or techniques currently used in the medical-related fields to study electron transfer in PD. related to electron transfer and PD. Methodology: Scopus, ScienceDirect, and EBSCOhost MEDLINE databases were used to search for literature related to electron transfer and PD. Results: From the thirty studies identified, PD appears to be caused by various causes, including increased levels of cytochrome c, reactive oxygen species produced by the mitochondria, dysfunction of complex I that interferes with the electron transfer process, and mitochondrial dysfunction triggered by PINK1 mutation. 6.7% of prior research has focused on utilizing DNA as a specific sample for investigating electron transfer in synthetic DNA through the use of STM. This highlights a notable lack of research into the potential of DNA in PD, despite the theoretical advantages that STM offers. Conclusions: We propose using STM as a new technique to study electron transfer in the DNA of PD from the physics perspective.

We present a method for motion-picture femtophotography that performs continuous, single-shot, burst image acquisition without the need for repetitive measurements. We capture the dynamics of laser ablation and phonon propagation with the imaging method.

The quantum spin magnet NH4CuCl3 is an antiferromagnetic dimer system, which has a magnetic ground state, and shows two‐stepped magnetization plateaus. The origin of the plateaus and the detailed spin structure is not well understood. We have investigated the NMR spectra of deuterated ND4CuCl3 in the field region of the first plateau. Resonance peaks of the Cl‐NMR spectra are classified into two groups with different temperature dependences. This indicates the existence of magnetically inequivalent dimers which are localized in space. Rotation profiles of the 2D‐NMR spectra show many small peaks, indicating that the NH4 molecules are oriented in a finite number of directions.

The Hall coefficient (RH) has been measured in 0.5% Zn‐doped La2−xSrxCu0.995Zn0.005O4 under high magnetic fields up to 12 T. With decreasing temperature, RH increases and begins to decrease below a temperature TRH. This characteristic temperature TRH has the local maximum around x = 0.195, and this Sr‐concentration coincides with that the superconducting transition temperature is slightly suppressed. This behavior is quite similar to the phenomena observed in the stripe phase in x ∼ 0.12. These results suggest that the anomalous decrease of RH around x = 0.195 observed in this study is responsible for the “1/4”‐anomaly [as reported by Kakinuma et al., Phys. Rev. B 59, 1491 (1999).].