Showing papers on "Nuclear quadrupole resonance published in 2007"

Exploiting Spin Echo Decay in the Detection of Nuclear Quadrupole Resonance Signals

Abstract: Nuclear quadrupole resonance (NQR) is a radio-frequency technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. In a typical application, one observes trains of decaying NQR echoes, in which the decay is governed by the spin echo decay time(s) of the resonant line(s). In most detection algorithms, these echoes are simply summed to produce a single echo with a higher signal-to-noise ratio, ignoring the decaying echo structure of the signal. In this paper, after reviewing current NQR signal models, we propose a novel NQR data model of the full echo train and detail why and how these echo trains are produced. Furthermore, we refine two recently proposed approximative maximum-likelihood detectors that enable the algorithms to optimally exploit the proposed echo train model. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed detectors offer a significant improvement as compared to current state-of-the-art detectors

Density Functional Theory Investigation of Hydrogen Bonding Effects on the Oxygen, Nitrogen and Hydrogen Electric Field Gradient and Chemical Shielding Tensors of Anhydrous Chitosan Crystalline Structure

Abstract: A systematic computational investigation was carried out to characterize the 17O, 14N and 2H electric field gradient, EFG, as well as 17O, 15N, 13C and 1H chemical shielding tensors in the anhydrous chitosan crystalline structure. To include the hydrogen-bonding effects in the calculations, the most probable interacting molecules with the target molecule in the crystalline phase were considered through a hexameric cluster. The computations were performed with the B3LYP method and 6-311++G(d,p) and 6-31++G(d,p) standard basis sets using the Gaussian 98 suite of programs. Calculated EFG and chemical shielding tensors were used to evaluate the 17O, 14N and 2H nuclear quadrupole resonance, NQR, and 17O, 15N, 13C and 1H nuclear magnetic resonance, NMR, parameters in the hexameric cluster, which are in good agreement with the available experimental data. The difference between the calculated NQR and NMR parameters of the monomer and hexamer cluster shows how much hydrogen bonding interactions affect the EFG and chemical shielding tensors of each nucleus. These results indicate that both O(3)-H(33)...O(5-3) and N-H(22)...O(6-4) hydrogen bonding have a major influence on NQR and NMR parameters. Also, the quantum chemical calculations indicate that the intra- and intermolecular hydrogen bonding interactions play an essential role in determining the relative orientation of EFG and chemical shielding principal components in the molecular frame axes.

Observation of Symmetry Lowering Associated with the Metal–Insulator Transition in SmRu4P12 by 101Ru-NQR

Abstract: We report the results of NQR (nuclear quadrupole resonance) study on SmRu 4 P 12 , one of a few candidates for materials showing octupolar ordering. In this study, we firstly succeeded in observing the 101 Ru-NQR signal in filled skutterudite compounds R Ru 4 P 12 ( R : rare earth). A single 101 Ru-NQR signal splits into two resonance lines, having intensity ratio of 3:1, just below the metal–insulator ( M – I ) transition temperature of 16.5 K. This result gives convincing evidence for symmetry lowering in the ordered state of this compound, namely the cubic I m \bar3 space group for the filled skutterudite compounds is lowered to the trigonal R \bar3. The model of the ordered structure characterized by a wave vector q =(1,0,0) satisfactorily explains the observed phenomena in the present study and the M – I transition in this compound.

Magnetic and Structural Studies of the Quasi-Two-Dimensional Spin-Gap System (CuCl)LaNb2O7

Abstract: We report magnetization, nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and transmission electron microscopy (TEM) studies on the quasi-two-dimensional spin-gap system (CuCl)...

RF Response of Superconducting-GMR Mixed Sensors, Application to NQR

Abstract: When coupled to a Giant Magneto-Resistive (GMR) sensor, a superconducting loop containing a constriction can be a very sensitive device for magnetic field detection . The bandwidth of a GMR sensor is wide with only a limitation in the GHz regime mainly due to the ferromagnetic resonances of the free layer. We have studied the radiofrequency response of this mixed sensor and we present femtotesla-range sensitivity obtained up to 10 MHz. An application of this kind of sensor is Nuclear Quadrupolar Resonance (NQR) and low field Nuclear Magnetic Resonance (NMR). We present results showing that mixed sensors can be better than optimized resonant coils for frequencies below 10 MHz opening new possibilities not only for magnetic imaging and low field Nuclear Magnetic Resonance but also for a lot of applications of magnetic sensing in the RF domain.

Manometer extension for high pressure measurement: nuclear quadrupole resonance study of Cu2O with a modified Bridgman anvil cell up to 10 GPa.

Abstract: We report C63u nuclear quadrupole resonance (NQR) measurement of Cu2O under pressure up to about 10 GPa at low temperatures. Because the lattice parameter of Cu2O changes with increasing pressure, the electric field gradient at the Cu site also changes correspondingly with pressure. This enables us to use the Cu2O as an in situ manometer for high pressure nuclear magnetic resonance/NQR up to about 9 GPa.

Connection between Charge Fluctuations and the Coherent Temperature in the Heavy-Fermion System SmOs4Sb12: A Sb121, 123 NQR Study

Abstract: We report {121, 123}Sb nuclear quadrupole resonance measurements under pressure in a novel heavy fermion (HF) system SmOs4Sb12. The nuclear spin-spin relaxation rate 1/T{2} exhibits a distinct peak near the coherent temperature of the Kondo effect. The isotope effect of 121Sb and 123Sb indicates that the peak in 1/T{2} is electrical in origin. The connection between the peak in 1/T{2} and the development of coherency of the Kondo effect is robust even under pressure. It is conjectured that charge fluctuation plays an important role in forming the HF state in SmOs4Sb12.

Experimental evidence for ferromagnetic spin-pairing superconductivity emerging in U Ge2: A Ge73 -nuclear-quadrupole-resonance study under pressure

Abstract: We report that a novel type of superconducting order parameter has been realized in the ferromagnetic states in UGe$_2$ via $^{73}$Ge nuclear-quadrupole-resonance (NQR) experiments performed under pressure ($P$). Measurements of the nuclear spin-lattice relaxation rate $(1/T_1)$ have revealed an unconventional nature of superconductivity such that the up-spin band is gapped with line nodes, but the down-spin band remains gapless at the Fermi level. This result is consistent with that of a ferromagnetic spin-pairing model in which Cooper pairs are formed among ferromagnetically polarized electrons. The present experiment has shed new light on a possible origin of ferromagnetic superconductivity, which is mediated by ferromagnetic spin-density fluctuations relevant to the first-order transition inside the ferromagnetic states.

NQR: From imaging to explosives and drugs detection

Abstract: The main aim of this work is to present an overview of the nuclear quadrupole resonance (NQR) spectroscopy capabilities for solid state imaging and detection of illegal substances, such as explosives and drugs We briefly discuss the evolution of different NQR imaging techniques, in particular those involving spatial encoding which permit conservation of spectroscopic information It has been shown that plastic explosives and other forbidden substances cannot be easily detected by means of conventional inspection techniques, such as those based on conventional X-ray technology For this kind of applications, the experimental results show that the information inferred from NQR spectroscopy provides excellent means to perform volumetric and surface detection of dangerous explosive and drug compounds

Phase transition and temperature dependent electronic state of an organic ferroelectric, phenazine-chloranilic acid (1: 1)

Abstract: The isotope effect of hydrogen motion in an organic ferroelectric, phenazine (Phz)–chloranilic acid (H2ca and D2ca for normal and deuterated compounds, respectively) co-crystal, was studied by 35Cl nuclear quadrupole resonance (NQR). Besides a ferroelectric transition at Tc = 253 K (303 K), a neutral-to-ionic transition was found below 170 K (200 K) for Phz–H2ca (Phz–D2ca). 1H–14N nuclear quadrupole double resonance measurements were also made in order to study the temperature dependent electronic state of Phz–(H/D)2ca. 14N NQR parameters suggested that donor orbital populations of the two nitrogen atoms in a phenazine molecule become nonequivalent (1.78 and 1.97) in the ferroelectric phase, while they are both equal to 1.89 in the paraelectric phase. In the ionic phase of Phz–D2ca, which was obtained by cooling below 188 K, they became 1.50 and 1.95, suggesting a proton transfer from D2ca to Phz.

Nuclear Quadrupole Resonance Detection of Explosives

Abstract: Publisher Summary This chapter gives the account of the detection of explosive devices. The detection can be classified into two schemes — ”seeing” the device and detecting a certain component which is common to all devices. X-ray imaging is a model example of the previous scheme. It gives an image of the contents of anitem under inspection. It is presented upon the operator to be acquainted with the explosive device. Metal detection is a very good example of the latter scheme. Almost all land mines contain no less than a little quantity of metal that can be detected through a metal detector. Evidently, many guiltless objects contain metal. The problem is separating the guiltless from the hazardous. To detect the explosive device without any hesitation is to detect it with the help of devices. The thermal neutron analysis and dual-energy X-ray give the specificity and issues of radiation, which can be challenging in some situations. This chapter discusses the nuclear quadrupole resonance (NQR). NQR stimulates and detects the radio frequency (RF) signals from certain nuclei in molecules of interest and are called explosives.

High-accuracy calculation of nuclear quadrupole moments of atomic halogens.

Abstract: Electric field gradients at the nuclei of halogen atoms are calculated using a finite field approach. The four-component Dirac-Coulomb Hamiltonian serves as the framework, all electrons are correlated by the relativistic Fock-space coupled cluster method with single and double excitations, and the Gaunt term, the main part of the Breit interaction, is included. Large basis sets (e.g., 28s24p21d9f4g2h Gaussian-type functions for I) are used. Combined with experimental nuclear quadrupole coupling constants, accurate estimates of the nuclear quadrupole moments are obtained. The calculated values are Q(35Cl)=-81.1(1.2) mb, Q(79Br)=302(5) mb, and Q(127I)=-680(10) mb. Currently accepted reference values [Pyykko, Mol. Phys. 99, 1617 (2001)] are -81.65(80), 313(3), and -710(10) mb, respectively. Our values are lower for the heavier halogens, corroborating the recent work of van Stralen and Visscher [Mol. Phys. 101, 2115 (2003)], who obtained Q(127I)=-696(12) mb in a series of molecular calculations.

Ferromagnetic Quantum Critical Fluctuations and Anomalous Coexistence of Ferromagnetism and Superconductivity in UCoGe Revealed by Co-NMR and NQR Studies

Abstract: Co nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies were performed in the recently discovered UCoGe, in which the ferromagnetic and superconducting (SC) transitions were reported to occur at $T_{\rm Curie} \sim 3$ K and $T_S \sim 0.8$ K (N. T. Huy {\it et al.}, Phys. Rev. Lett. {\bf 99} (2007) 067006), in order to investigate the coexistence of ferromagnetism and superconductivity as well as the normal-state and SC properties from a microscopic point of view. From the nuclear spin-lattice relaxation rate $1/T_1$ and Knight-shift measurements, we confirmed that ferromagnetic fluctuations which possess a quantum critical character are present above $T_{\rm Curie}$ and the occurrence of ferromagnetic transition at 2.5 K in our polycrystalline sample. The magnetic fluctuations in the normal state show that UCoGe is an itinerant ferromagnet similar to ZrZn$_2$ and YCo$_2$. The onset SC transition was identified at $T_S \sim 0.7$ K, below which $1/T_1$ of 30 % of the volume fraction starts to decrease due to the opening of the SC gap. This component of $1/T_1$, which follows a $T^3$ dependence in the temperature range of $0.3 - 0.1$ K, coexists with the magnetic components of $1/T_1$ showing a $\sqrt{T}$ dependence below $T_S$. From the NQR measurements in the SC state, we suggest that the self-induced vortex state is realized in UCoGe.

Applications of nuclear quadrupole resonance spectroscopy in drug development.

Abstract: In this review, fundamentals of nuclear quadrupole resonance (NQR) spectroscopy are briefly outlined. Examples of its applications in drug development are discussed to demonstrate that the NQR method is a sophisticated, non-destructive and valuable analytical technique for studying pharmaceuticals, providing effective assistance at the two main steps of drug development: the physical and chemical characterization of the active pharmaceutical ingredients (API) at the analytical step and API development. This review covers different aspects of the use of NQR spectroscopy for drug development and analysis and illustrates the power and versatility of this method in the determination of impurities, polymorphic forms, the drug's structure and conformation, characterization of the interactions between the drug and ligands, search for analogs (second- or third-generation drugs) and the drug's thermal stability. Lastly, NQR advantages and restrictions in the aspect of application in drug development studies are summarized.

Evidence for point nodes in the superconducting gap function in the filled skutterudite heavy-fermion compound PrOs4Sb12 : 123Sb-NQR study under pressure

Abstract: We report 123 Sb nuclear quadrupole resonance (NQR) measurements of the filled skutterudite heavy-fermion superconductor PrOs 4 Sb 12 under high pressures of 1.91 and 2.34 GPa. The temperature dependence of NQR frequency and the spin-lattice relaxation rate 1/ T 1 indicate that the crystal-electric-field splitting Δ CEF between the ground state Γ 1 singlet and the first excited state Γ 4 (2) triplet decreases with increasing pressure. The 1/ T 1 below T c = 1.55 K at P = 1.91 GPa shows a power-law temperature variation and is proportional to T 5 at temperatures considerably below T c , which indicates the existence of point nodes in the superconducting gap function. The data can be well fitted by the gap model Δ(θ) = Δ 0 sin θ with Δ 0 = 3.08 k B T c . The relation between the superconductivity and the quadrupole fluctuations associated with the Γ 4 (2) state is discussed.

Evaluation of Pressure Transmitting Media by 63Cu-NQR of Cu2O

Abstract: High pressure technique up to about 3GPa is now widely used in studies of condensed matter physics. This is due to the development of hybrid cylinder clamp cells, especially CuBe/NiCrAl and CuBe/MP35N. Further high pressures can be achieved by Bridgman anvil cell (up to about 10GPa), cubic anvil cell (up to about 20GPa) and diamond anvil cell (up to about 400GPa), and so on. Optical measurements and electric resistivity measurement with the use of the diamond anvil cell are now conventional methods for high pressure measurements beyond about 100GPa. However, other major measurements such as neutron diffraction, nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and muon spin relaxation ( SR) have technical difficulty since large sample space is essentially needed for these methods. Of these methods, NMR/NQR under high pressure is relatively accessible. We indeed reported Cu-NQR measurements of Cu2O up to about 10GPa by using a modified Bridgman anvil cell which is designed for general-purpose pressure cell. In our previous NQR measurements of Cu2O, the spectral broadening was observed and was nearly proportional to pressure P. This was ascribable to the existence of inhomogeneous pressure distribution inside the cell and/or local shear of the crystalline lattice, induced by the uniaxial stress of the inhomogeneous pressure. A reason of the pressure inhomogeneity except for the problem, originating from the Bridgman anvil cell itself, is that the pressure transmitting medium is already solid at high pressures. Generally, the solid pressure transmitting media make the pressure distribution inside the cell inhomogeneous. However, it is difficult to avoid solidification of the pressure media at high pressures. Hence, it is vital to choose the most appreciate medium for high pressure measurements. The NMR/NQR technique has an advantage to investigate the suitability of the pressure media because the pressure inhomogeneity inside pressure cell is strongly related to the broadening of NMR/NQR spectra. In this paper, we report Cu-NQR measurement of Cu2O with the currently representative liquid pressure-transmitting media. As the first step of the investigation, we demonstrated the NQR experiments under pressure up to about 3GPa at low temperature and room temperature. There are some reports on the liquid pressure-transmitting media, but few appeared in refereed journals. Moreover, to the best of our knowledge, there is no report of the evaluation and the comparison of the pressure media from the viewpoint of NMR/NQR technique. Therefore, we evaluated the pressure quality of the representative pressure-transmitting media by NQR. The Cu-NQR measurements of Cu2O were performed using a phase-coherent pulsed NQR spectrometer in the resonance frequency range 26–28MHz. We used commercial Cu2O powder (99.9%). We performed the NQR measurements at 4.2K and room temperature (about 300K). The obtained spin echo data were Fourier transformed to NQR spectra. In most cases, the line shape at a pressure was obtained at an excitation resonance frequency. We used conventional Cu-Be/NiCrAl hybrid piston cylinder cell. Single-layer coil wound about 20 turns was used in our measurements ( 1⁄4 3mm, l 1⁄4 5mm). The diameter of the initial sample space was 4.5mm and its length was 18mm. We used the following four representative liquid pressure-transmitting media: a 1 : 1 mixture of Fluorinert 70 and 77 (Fluorinert), Daphne 7373 oil (Daphne), a 1 : 1 mixture of n-pentane and isopentane (Pentane), and glycerin (Glycerin). We did not try a mixture of methanol and ethanol since this mixture sometimes dissolves the epoxy which is used for the pressure seal of the piston cylinder cell. Note that the configuration of the sample and the sample coil except for the pressure media was always the same inside the cell in order to compare the contribution of only the pressure media to the NQR spectra. The frequency f dependence of Cu-NQR resonance frequency of Cu2O up to about 9GPa can be used for a pressure manometer. In our previous NQR measurements of Cu2O, we revealed that the calibration formula reported by Reyes et al. is basically consistent with our extended calibration formula. Because our calibration formula was obtained only at low temperature, we used the calibration formula reported by Reyes et al. in this study, which covers the temperature range between 4.2 and 350K and the pressure range up to about 2GPa. We determined the pressure beyond 2GPa by the extrapolation of this formula. We clarified its appropriateness in our previous study. The calibration formulae are f ðP; 4:2KÞ 1⁄4 26:82þ 0:402P 1:496 10 P and f ðP; 300KÞ 1⁄4 25:99þ 0:355P 6:738 10 P. Here, f and P are in MHz and in GPa, respectively. With these formulae and the spectral center f of NQR of Cu2O, we derived pressure inside the cell. In Fig. 1, we show the P dependence of the full width at half maximum (FWHM) of Cu-NQR spectra of Cu2O with the various pressure transmitting media, Fluorinert, Daphne, Pentane, and Glycerin. The data are obtained at room temperature [about 300K, Fig. 1(a)] and 4.2K [Fig. 1(b)]. The accuracy of the data is within 5%. In the inset of Fig. 1(b), we show the Cu-NQR spectra of Cu2O obtained at room temperature under the pressures of 2.15GPa (Fluorinert) and 2.29GPa (Pentane). The most obvious feature of the results is the P dependence of the FWHM of the Fluorinert. The FWHM of the Fluorinert linearly increases with increasing P. This is clear in the inset of Fig. 1(b), which shows that the line shape of the Fluorinert is much broader than that of the E-mail: hideto@nmr.s.chiba-u.ac.jp Journal of the Physical Society of Japan Vol. 76, No. 12, December, 2007, 125001 #2007 The Physical Society of Japan

Improved N14 nuclear quadrupole resonance detection of trinitrotoluene using polarization transfer from protons to N14 nuclei

Abstract: Combination of proton-nitrogen level crossing polarization transfer and pulsed spin-locking sequence makes N14 nuclear quadrupole resonance (NQR) in trinitrotoluene fast and sensitive enough to be used in routine detection of explosives. Enhancement factors for all three N14 NQR lines (the case with η≠0) were calculated and compared with experimental values. Good agreement between measured and calculated signal enhancement factors was observed. N14 NQR signals in a 15g trinitrotoluene sample of predominantly monoclinic modification were measured in 15s in different polarization magnetic fields. The conditions for optimal proton-nitrogen level crossing were determined.

Evidence for Point Nodes in the Superconducting Gap Function in the Filled Skutterudite Heavy-Fermion Compound PrOs4Sb12: 123Sb-NQR Study under Pressure

Abstract: We report $^{123}$Sb nuclear quadrupole resonance (NQR) measurements of the filled skutterudite heavy-fermion superconductor PrOs$_4$Sb$_{12}$ under high pressures of 1.91 and 2.34 GPa. The temperature dependence of NQR frequency and the spin-lattice relaxation rate $1/T_1$ indicate that the crystal-electric-field splitting $\Delta_{\rm CEF}$ between the ground state $\Gamma_1$ singlet and the first excited state $\Gamma_4^{(2)}$ triplet decreases with increasing pressure. The 1/$T_1$ below $T_c$ = 1.55 K at $P$ = 1.91 GPa shows a power-law temperature variation and is proportional to $T^5$ at temperatures considerably below $T_c$, which indicates the existence of point nodes in the superconducting gap function. The data can be well fitted by the gap model $\Delta(\theta)=\Delta_0\sin\theta$ with $\Delta_0$ = 3.08$k_{\rm B}T_{\rm c}$. The relation between the superconductivity and the quadrupole fluctuations associated with the $\Gamma_4^{(2)}$ state is discussed.

75As-NQR Studies of Superconducting Filled Skutterudites PrRu4As12 and LaRu4As12

Abstract: We report 75 As nuclear quadrupole resonance (NQR) measurements of the filled skutterudite superconductors LaRu 4 As 12 and PrRu 4 As 12 . The temperature dependence of the 75 As-NQR line and the n...

Unconventional Pairing States in Heavy-Fermion Superconductors Studied by the NQR/NMR Experiments

Abstract: We review the studies on the unconventional superconducting pairing states and their relevance with magnetism in the f -electron derived heavy-fermion (HF) systems by means of nuclear-magnetic-reso...

Using Spatial Diversity to Detect Narcotics and Explosives Using NQR Signals

Abstract: Nuclear quadrupole resonance (NQR) offers an unequivocal method of detecting hidden narcotics and explosives. Unfortunately, the practical use of NQR is restricted by the low signal-to-noise ratio (SNR) and means to improve the SNR are vital to enable a rapid, reliable and convenient system. In this correspondence, we develop two multichannel detectors to counter the typically present radio frequency interference. Numerical simulations indicate that the proposed methods offers a significantly improved robustness to uncertainties in the parameters detailing the examined sample.

T–3νQ Phase Diagram of Hydrated Cobalt Oxides NaxCoO2·yH2O

Abstract: The superconducting transition temperatures of Na x CoO 2 · y H 2 O prepared by various methods have been found to exhibit the systematic dependence on the nuclear quadrupole frequency ν Q . In the...

Low-field approach to double resonance in nuclear quadrupole resonance of spin-1 nuclei

Abstract: Using double-resonance conditions, in which the Larmor frequency of a spin-1∕2 nucleus is matched to one of the nuclear quadrupole resonance frequencies of a spin-1 nucleus, the authors demonstrate increased cross relaxation between the two nuclear spin species. They calculate the cross-relaxation rate using the motionally averaged heterogeneous dipole Hamiltonian as a perturbation to the combined quadrupole and Zeeman Hamiltonians. Using this cross-relaxation rate, in addition to hydrogen and nitrogen autorelaxation rates, expressions governing spin-1∕2 and spin-1 spin-lattice relaxation are determined. With ammonium nitrate, containing nitrogen (spin-1) and hydrogen (spin-1∕2), increased nitrogen signal and spin-lattice relaxation are demonstrated, using fields less than 120G. The cross-relaxation rate is also measured and an overall signal/noise improvement by a factor of 2.3±0.1 is attained.

Nuclear quadrupole resonance study of the electronic properties of the narrow-gap semiconductor Fe Sb 2

Abstract: Electronic properties of the narrow-gap semiconductor $\mathrm{Fe}{\mathrm{Sb}}_{2}$ have been studied by the magnetization and $^{121∕123}\mathrm{Sb}$ nuclear quadrupole resonance measurements. In addition to the susceptibility, the spin-lattice relaxation rate has revealed a fully opened gap at the Fermi level. The relaxation process is dominated by the magnetic contribution at high temperature $T$, while the quadrupole contribution becomes dominant below $70\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Electronic field gradient at Sb sites shows anisotropic $T$ dependence, reflecting most probably the anisotropic thermal expansion.

Unusual Suppression of Low Energy Spin Excitations near Fermi Level in AFe4Sb12 (A=Ca, Sr, and Ba) Probed by Sb-NQR

Abstract: Sb nuclear quadrupole resonances (NQR) have been performed on the alkaline-earth filled skutterudite A Fe 4 Sb 12 ( A =Ca, Sr, and Ba) being close to ferromagnetic instabiity. No hyperfine splitting in NQR spectrum even at the lowest temperature (1.5 K) confirms an absence of uniform ferromagnetic order in these compounds. Above about T * ∼70 K, the nuclear spin–lattice relaxation rate divided by temperature, 1/ T 1 T , follows an empirical relationship 1/ T 1 T = a + b χ spin with respect to the Curie Weiss (CW) like T -dependence of the static spin susceptibility χ spin . The correlation between 1/ T 1 T and χ spin is consistent with the self-consistent renormalization (SCR) theory for the three-dimensional (3D) nearly ferromagnet despite the relatively large contribution of the first term not correlating to χ spin . However, below about T * , 1/ T 1 T exhibits a gap-like suppression with a gap magnitude of about 65 K. This unusual suppression of the low energy spin excitations is contrasting to the cas...