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The paramagnetic g -value and linewidth of Nd 0.5 Sr 0.5 MnO 5 single crystal show the presence of spin clusters in the paramagnetic state. The anisotropy field splits the spectra below 250 K ( T C ). An A-type antiferromagnetic phase ( T N ∼ 225 K) is found to coexist with the ferromagnetic phase down to the charge ordering temperature of 150 K, at which a transition takes place also to a CE-type antiferromagnetic state.

Single crystals of the rare earth hexaborides have been grown successfully by the floating zone technique using a high-power Xenon arc Image furnace. Large, high-quality crystals up to 1 cc in volume have been obtained for several rare earth hexaborides by this method. Crystals of these compounds have also been grown using enriched 11 B isotope for use in neutron scattering studies. The crystal growth and characterisation of these crystals are reported in the paper.

Results of ultrasonic studies of the magnetoresistive compound Nd 0.5 Sr 0.5 MnO 3 in a broad temperature range (1.5–180 K) are reported. With decreasing temperature the pronounced acoustic mode hardening was observed at about T CO =145 K. The change of sound velocity around T CO was explained by a strong coupling between the acoustic phonons and the charge-ordered states.

The magnetic phase diagram of the triangular lattice antiferromagnet CuFeO 2 has been studied using single-crystal neutron diffraction measurements in a magnetic field of up to 14.5 T and also by magnetisation measurements up to 12 T. At low temperature, two well-defined first-order magnetic phase transitions were found in this range of applied magnetic field: at H C1 =7.6 T and H C2 =13.2 T, with the later one corresponding to a transition from a four to five sublattice structure. Cooling the sample in a high magnetic field resulted in the locking of the magnetic structure into the intermediate temperature incommensurate structure.

Inelastic neutron scattering has been used to study the spin dynamics of CePd 3 B x alloys. The very large quasielastic linewidth found in CePd 3 decreases very rapidly with addition of interstitial boron. For x ≈ 0.3 the lineshape clearly shows both quasielastic and inelastic components, arising from the crystal field splitting of the 4f 1 state. The temperature dependence of the spectra shows that the ground state is the quarlet T 8 .

Metals on the verge of and just in the weakly magnetic state offer a unique test ground for current theories of itinerant magnetism. TiBe 1.5 Cu 0.5 becomes ferromagnetic below 27 K with a low temperature moment of 0.07μ B per average atom. Using the temperature and wavevector dependence of small angle neutron scattering data we have investigated the spectrum of low energy spin dynamics both in the magnetically ordered and disordered phases. Over the experimentally accessible range the low wavevector excitations are characterized by damped spin waves which evolve continuously into overdamped diffusive modes above T c .

Neutron scattering has been used to observe diffraction from the flux-line lattice in high temperature superconductors. This technique is particularly useful in such systems as it allows observations to be made over a wide range of temperature and magnetic field. Experiments on the systems K0.4Ba0.6BiO3 and YBa2Cu3O7−δ will be described with applied magnetic fields of up to 4 T and for temperatures from 2 K to Tc.

We present new results for the spin wave dispersion relation measured along the [ξξ0] direction in bcc iron (12% silicon) by time-of-light, neutron inelastic scattering. The excitations were followed to the zone boundary, where they are spread over a range of energies around 300 meV.

The magnetic properties of a single crystal of the ‘electron superconductor’ Nd 1.85 Ce 0.15 CuO 4− y , have been investigated for applied fields parallel and perpendicular to the basal plane ( ab ). The lower critical field, H c1 , the magnetic susceptibility and the high field magnetization are all found to be strongly anisotropic. The observed magnetic susceptibility is analysed based on the influence of crystal field effects on Nd 3+ ion and the parameters obtained are consistent with the reported crystal field transitions observed experimentally.

The onset of ferromagnetic order in TiBe 2- x Cu x alloys, with x = 0.5, 0.4, 0.3, 0.2 and 0.15, has been examined using the technique of neutron small-angle scattering. The Curie temperature, T c , for these alloys has been determined from the temperature dependence of the magnetic critical scattering. A linear extrapolation of T c versus copper concentration yields a critical concentration for ferromagnetic order of x c = 0.05 ± 0.02. For the alloys with x = 0.4, 0.5 the lineshape of the magnetic critical scattering, at and above T c , is well explained by the Ornstein-Zernicke form of the spin correlation function. For the lower concentration alloys the exact form of the spin correlation function is still unclear.