[en] The magnetic phases of the heavy rare-earth metal thulium below the Neel temperature of 56 K have been examined in magnetic fields up to 7 T. The thermal expansion and magnetostriction of a Tm single crystal were studied along the c-axis, using a capacitance dilatometer. A number of new magnetic phases appear in non-zero magnetic fields. These are intermediate phases between the c-axis modulated and 4 up, 3 down ferrimagnetic phases previously established. (orig.)

[en] The rare-earth metal neodymium exhibits a hierarchy of 1-q, 2-q, 3-q and 4-q magnetic structures below T_N = 19.9 K. Magnetostriction and thermal expansion measurements have revealed more than 10 phases in the magnetic phase diagram for fields up to 5 T. These phases have been identified by neutron diffraction studies. Some of them are characterised by the appearance of subharmonics of the fundamental modulation wavevector. A new model for the structure of these phases is proposed. (orig.)

[en] Magnetic multilayers are known to have behaviour shaped by the intrinsic magnetic properties of their constituents and of their interactions. Multilayers composed of Uranium (5f electrons) and transition metal (3d electrons) provide the unique combination of a potentially large orbital moment with strong electronic hybridisation effects between the extended 5f states and the strongly magnetic 3d states. In this study U/Fe multilayers with layer thicknesses 20 A< U<100 A and 30 A< Fe<140 A were fabricated by dc sputtering in a UHV chamber. X-ray reflectivity (XRR) spectra show good layer structure with little interdiffusion at interfaces. We have investigated the magnetic moment profile normal to the layers by polarised neutron reflectivity (PNR) and specifically whether magnetic moments are induced on the uranium layers by the proximity of the iron layers. The PNR results show a magnetic moment on the iron layers reduced from that of pure bcc iron and they set an upper limit on any moment on the U layers. A more sensitive search for the U moment has involved resonant X-ray magnetic reflectivity measurements at energies around the UM_IV edge using different geometries of circular polarisation helicity and applied magnetic field. Some evidence of U moments has been observed

[en] The magnetic phase diagrams of Nd, for fields up to 12 T applied parallel to the crystallographic a-,b- and c-directions, have been constructed from observed anomalies in thermal expansion and longitudinal magnetostriction measurements. The results are interpreted with reference to neutron diffraction studies and in terms of multi-domain single-q, double-q, triple-q and quadruple-q structures. (author)

[en] The cubic Laves-phase compound HoCo₂ orders magnetically at 76 K. Its moment undergoes a reorientation with increasing temperature from left angle 110 right angle to left angle 100 right angle in the temperature interval 10 to 17 K. The substitution of Rh for Co does not vary the crystal field parameters to any appreciable extent, but does alter the value of the exchange interaction, so that the series Ho(Co_1-cRh_c)₂ is particularly suitable for the investigation of the spin reorientation. The results of thermal expansion measurements on these compounds are presented and compared with theoretical investigations. It is shown that a single-ion Hamiltonian used in conjunction with suitably chosen crystal-field and exchange parameters can satisfactorily describe the spin reorientation transition. The 's-d' model is used to determine magnetic and related parameters of the series and is found to account quite well for the changing character of the magnetic phase transition. (orig.)

[en] The magnetic phase diagram of erbium has been constructed from the observed anomalies in thermal expansion and longitudinal magnetostriction measurements. Using a capacitance dilatometer, single crystal measurements were made parallel to the crystallographic c-axis in the temperature range 2-100 K and in fields up to 7 T. Features of the phase diagram are compared with those of diagrams deduced from previous neutron scattering studies. ((orig.))

[en] The localised-moment system UPd₃ exhibits quadrupolar and magnetic phase transitions, at T₁∼7 K and T₂∼4.5 K, respectively. We have followed the magnetic field dependence of the transitions in thermal expansion and magnetostriction measurements. The thermal expansion is large and highly anisotropic, as is the magnetostriction below T₂. The transitions are extremely sensitive to Pt doping. ((orig.))

[en] The results of calorimetry from 2 to 12K on single crystals of localised-moment UPd₃ in magnetic fields of zero and 6T applied along the crystallographic c-direction are presented. Three anomalies in the specific heat were observed which coincide with anomalies in magnetic thermal expansion. The different field-dependencies of these transitions are reported. Combining the two measurements we are able to map the changes in the zero-field Grueneisen parameter across the three transitions. ((orig.))

[en] Thermal expansion and magnetostriction measurements have been made on the cubic Laves-phase alloys Ho(Co_1-xRh_x)₂ in the temperature range 2 to 110 K and in fields up to 7 T. The samples were polycrystalline, with x=0.00, 0.02, 0.05, 0.08, 0.12, 0.16 and 0.25. Two thermal expansion anomalies are observed at a ferromagnetic transition and a spin-flop transition. The change in temperature and ordering nature of these transitions is reported as a function of Rh concentration. Magnetostriction measurements show a marked variance with Rh concentration and suggest the presence of three new distinct magnetic phases. ((orig.))

[en] Thermal expansion and magnetostriction measurements are reported for single-crystal UNi₂Si₂. For magnetic fields up to 15 T applied along the c direction and in the temperature range 2-150 K distinct features and anomalies observed in the combined results are used to construct a magnetic phase diagram. The diagram extends that deduced from neutron scattering work at low fields. ((orig.))