Nuclear magnetic resonance of 55Mn and 75As in MnAs

Four sets of NMR signals, two each, from ⁵⁵Mn and ⁷⁵As nuclei have been observed. The temperature dependences of ⁵⁵Mn resonances have been studied from 77 to 311 K and that of ⁷⁵As, from 77 K to about 250 K. The results show that there is a phase transition at T₁ ≈ 220 K. This transition may be due to introduction of a local spontaneous distortion in the region of the domain walls in the lattice, resulting in lowering of symmetry at low temperatures. Another possibility is the canting of spins which would lower the magnetic group symmetry. The observed resonances have been assigned to arise from the nuclei at the edge and the centre of the domain walls at temperatures T >T₁ and from two types of wall edges with inequivalent orientation of atomic spins at T < T₁. The isotropic hyperfine field at 0 K obtained by extrapolating the resonance frequencies are 227 and 285.1 kOe at ⁵⁵As nuclei, respectively. The anisotropy in the hyperfine field is nearly zero at ⁵⁵Mn nuclei and about 5.8 kOe at ⁷⁵As nuclei at 0 K.     

Nuclear magnetic resonance of 59Co on A and B sites in Co3S4

A comment is made on a recent paper by Saji and Yamadaya, who erroneously attribute a single cobalt NMR line in Co₃S₄ to cobalt at the B sites of the spinel lattice. A summary is given of earlier published work which describes cobalt NMR at both A and B sites.     

59Co nuclear magnetic resonance in antiferromagnetic CsCoCl3

The ⁵⁹Co NMR in a CsCoCl₃ single crystal has been observed by the spin echo method at 4.2 K. The obtained spectrum is composed of seven distinct lines split by the nuclear-quadrupole interaction. The frequency of the central (± $\text{1}\text{2}$ ? ± $\text{1}\text{2}$) transition 502.08±0.05 MHz corresponds to the hyperfine field of 499.38 ± 0.05 kOe, which agrees well with the calculated value. Due to the interaction of the nucleus with the electronic moment induced by the external field, a shift as large as 18% was observed for the nuclear g-factor.     

Nuclear magnetic resonance of 131I and 132I oriented in Fe

Nuclear magnetic resonance has been applied to radioactive I nuclei oriented in Fe. By field shifting the ¹³¹I resonance the hyperfine field is determined as positive. The ¹³¹I resonance at 683.3 ± 1.0 MHz and the ¹³²I resonance at 674.0 ± 0.5 MHz give H_int = 1144.0 ± 1.5 kOe.     

Nuclear magnetic resonance of 11B in CrB2

From measurements of the ¹¹B NMR in CrB₂ the transferred hyperfine field due to the neighboring magnetic moments of Cr and the temperature dependence of T₁ have been investigated. It is suggested that CrB₂ is not in the weakly itinerant antiferromagnetic regime but is in the stronger or intermediate regime.     

Nuclear magnetic resonance in ferromagnetic terbium

The temperature dependence of the magnetic dipole and electric quadrupole hyperfine fields has been measured by NMR in ferromagnetic terbium metal. The results are in excellent agreement with a general theoretical relation connecting moments of the magnetization. This relation allows us to separate ionic and crystalline contributions to the nuclear electric field gradient.     

Nuclear magnetic resonance of 27Al in the lutetium aluminum garnet

By NMR, the quadrupole coupling constants of ²⁷Al for the a- and d-sites in Lu₃Al₂ (AlO₄)₃ have been determined at 300 and 4.2 K. Structural consequences are discussed and compared with other rare earth aluminum garnets.     

Nuclear magnetic resonance on the 10−, 0.88 ms state in 206Bi

Alpha-particle reduced widths for the 8⁺ state at 11.95 MeV, obtained from analysis of both ¹⁶O + α resonant scattering data and ¹⁶O(⁶Li, d)²⁰Ne reaction data are consistent with expectation for the 8⁺ member of the ground-state rotational band.     

Gamma transitions in 59Ni following the β+ decay of 59Cu

The γ-ray decay spectrum of 82 s ⁵⁹Cu produced by the ⁵⁸Ni(p, γ) ⁵⁹Cu reaction has been studied with a 40 cm³ Ge(Li) detector. The number of γ-rays now known for this decay has more than doubled. Additional direct β⁺ branches to the 1679.7($\text{5}\text{2}{}^{\mathrm{?}}$), 2414.8($\text{3}\text{2}{}^{\mathrm{?}}$) and 2681 keV states of ⁵⁹Ni have been identified with log ft values of 5.5, 5.5 and 6.0, respectively. A major change is the reassignment of the 1340.4 keV γ-ray to a 1679.7 → 339.3 keV transition. A limit of log $\text{ft ≧ 6.9}$ is given for the direct feeding of the 1337($\text{7}\text{2}{}^{\mathrm{?}}$) keV state, together with limits for direct population of other energetically available states. The new weak γ-ray branches found for the 878.0, 1301.5 and 1679.7 keV levels are in excellent agreement with the recent theoretical calculations of Glaudemans et al.     

Nuclear magnetic resonance of 9Be atoms by charge exchange with optically pumped 9Be+ ions

NMR of free ${}^9\text{Be}\text{(I =}\text{3}\text{2}\text{)}{}^1\text{S}{}_0$ atoms is observed via resonant charge exchange with optically pumped ${}^9\text{Be}{}^{\mathrm{+}}{}^2\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ ions in He buffer gas, yielding $\text{μ(}{}^9\text{Be}\text{) = ?1.1778 (9) μ}{}_{\mathrm{<mtext>n</mtext>}}$. Applications of the method suitable for all group II elements and Yb include: precision measurements of nuclear moments, chemical shifts, hfs-anomalies, and investigation of charge exchange processes.     

Ultrasonic attenuation in HCP 4He crystals

Measurements of the attenuation of longitudinal sound at frequencies of 5–50 MHz have been made at 1.70 K in hcp ⁴He crystals at a molar volume of 20.5 cm³/mole and of various crystallographic orientations. The frequency and orientation dependence of the attenuation can reasonably be explained by the vibrating string model of dislocations.     

The 59Co nuclear magnetic resonances in the intermetallic compounds

The anisotropic hyperfine fields of the intermetallic compounds have been studied by the spin echo method and were obtained from the NMR spectra of ⁵⁹Co nuclei in ThCo₅ and YCo₅ which have the high anisotropy fields resulting from the orbital moments. The intermetallic compounds, ThCo_5.3 and YCo_5.3, have been also investigated.     

55Mn nuclear magnetic resonance in Mn2Sb

The observation of NMR signals from ⁵⁵Mn nuclei in Mn₂Sb has been reported. A temperature variation study of the domain and domain wall signals in Mn₂Sb confirms that the magnetization is aligned parallel to the c-axis at temperatures higher than 240 K and that it is in the basal plane below 240 K. The temperature dependence of the anisotropy in the hyperfine field at the Mn(I) and Mn(II) sites has been determined.     

High-spin states in 59Ni

High-spin states in ⁵⁹Ni have been investigated via the study of in-beam γ-rays following the reactions ⁵⁰Cr(¹²C, 2pn)⁵⁹Ni (26–58 MeV) and ⁵⁶Fe(α, n)⁵⁹Ni (10, 15, 22.5 MeV). The spins of previously known levels have been confirmed or determined for the first time, in particular for those at $\text{3376.8}\text{keV}\text{(J =}\text{11}\text{2}\text{)}\text{and}\text{4141.3}\text{keV}\text{(J =}\text{13}\text{2}\text{or}\text{15}\text{2}\text{)}$. New states have been established and their spin determined, at $\text{1739.2}\text{keV}\text{(J =}\text{9}\text{2}\text{), 2349.2}\text{keV}\text{(J =}\text{11}\text{2}\text{), 2535.5}\text{keV}\text{(J =}\text{13}\text{2}\text{), 4455.4}\text{keV}\text{(J =}\text{13}\text{2}\text{), 4947.5}\text{keV}\text{(J =}\text{15}\text{2}\text{)}\text{and}\text{5251.7}\text{keV}\text{(J =}\text{13}\text{2}\text{or}\text{15}\text{2}\text{)}$. The resulting ⁵⁹Ni decay scheme is discussed in the framework of nuclear models.     

Nuclear ferromagnetic resonance on Co2B and on some dilute alloys

The NMR of Co⁵⁹ at 4.2 K in the compound Co₂ B and in the series (Co_0.99X_0.01)₂B where X = Ti, V, Cr, Mn, Fe and Ni is developed in this paper. The NMR spectrum of Co₂B shows a single narrow line which indicates that the easy magnetization direction is parallel to the tetragonal axis. In a static external field the shift of the line indicates that the hyperfine field is negative.Spin-lattice relaxation time T₁ measurements show that the density of states at the Fermi level reaches a maximum in the vicinity of X = V, Cr, in agreement with previous magnetic, resistivity and specific heat investigations. These results are interpreted by the virtual bound state concept.     

51V nuclear magnetic resonance in polycrystalline ferroelastic BiVO4

Nuclear magnetic resonance studies on polycrystalline ferroelastic BiVO₄ indicate that the ⁵¹V electric field gradient asymmetry parameter is an order parameter in the ferroelastic transition. Using ∩ = A(T?T_c)^B, B is found to be 0.48(5), in good agreement with earlier studies of this material. Near the phase transition above and below, the vanadium nuclear quadrupole coupling is constant with a value of 4.8(1) MHz.     

Nuclear magnetic resonance (NMR) study of 73Ge in Ge[Co2]O4

Nuclear magnetic resonance of ⁷³Ge in Ge[Co₂]O₄ was investigated between 77°K and 290°K. Analysis on resonance shifts showed a presence of considerable everlap between the oxygen and germanium ions, suggesting the long-range superexchange interaction via CoOGeOCo paths.     

Chemical synthesis and magnetic properties of HCP and FCC nickel nanoparticles

In this study, we successfully synthesized single-phase hexagonal closed packed (HCP) and face-centered cubic (FCC) nickel nanoparticles via reduction of nickel nitrate hexahydrate and nickel acetate tetrahydrate, respectively, in polyethylene glycol-200. Structural information of the as-synthesized nickel nanoparticles are studied by X-ray diffraction (XRD) as a function of the molar concentration of the nickel precursor. XRD results reveal that low concentrations of nickel precursor (0.005?M and below) favor the HCP, while high concentrations favor the mixture of HCP and FCC crystal structures. Particle size of HCP structure is found in the range of ～15?nm via transmission electron microscope analysis. Vibratory sample magnetometer is employed to study its magnetic behavior and the results reveal that FCC crystalline phase shows ferromagnetic nature with high saturation magnetization (M _s?～?39.6?emu?gm^?1) as compared to metastable HCP crystalline structure (M _s?～?2?emu?gm^?1). The surfactants bonding on the surface of nickel nanoparticles are studied.