An evaluation of an employment project for mentally ill people

This thesis is concerned with the rehabilitation and employment of mentally ill people. It focusses on a Community Programme which offers a year's employment to people with a mental illness. Fifty -three people recruited to the Sprout project were interviewed at various stages during their career on the project. The study sets out to evaluate the project's impact on participants, both during their employment there and subsequently. Participants' views on employment in general and on Sprout were obtained, along with details of their employment and psychiatric histories and of their social circumstances.At a time of high general unemployment, there is much debate about the emphasis work should be given in rehabilitation. In the thesis, I rehearse some of the arguments and counterarguments and consider what light the views of service -users can throw on the issue. It emerges that many mentally ill people believe that they benefit from being in work. They want to work and, given a supportive setting, are capable of doing so. However, there were few opportunities for those leaving Sprout to take up either sheltered or open employment elsewhere.The outcomes for Sprout participants were highly diverse and it seems imperative that such diversity should be reflected in a range of provision which catered for variations in ability and interest. To polarise discussion and debate whether or not work has a place in rehabilitation seems unhelpful.The project had, on the whole, disappointingly little long -term effect on the abilities and quality of life of participants. However, when viewed in the context of other research findings, these results are not surprising as rehabilitation rarely succeeds in bringing about lasting improvements in ability. Moreover, it was evident that Sprout participants often faced substantial difficulties in their lives outside work and yet received little or no support from health or welfare services. This may have affected outcome.The thesis points up deficiencies in current services for mentally ill people and suggests ways in which the employment opportunities of this group might be enhanced. It is insufficient to look only at the employability of the individuals concerned, without also considering the wider social factors which influence access to and retention of employment

Angular variation of the magnetoresistance of the superconducting ferromagnet UCoGe

We report a magnetoresistance study of the superconducting ferromagnet UCoGe. The data, taken on single-crystalline samples, show a pronounced structure at $B^* = 8.5$~T for a field applied along the ordered moment $m_0$. Angle dependent measurements reveal this field-induced phenomenon has an uniaxial anisotropy. Magnetoresistance measurements under pressure show a rapid increase of $B^*$ to 12.8~T at 1.0~GPa. We discuss $B^*$ in terms of a field induced polarization change. Upper critical field measurements corroborate the unusual S-shaped $B_{c2}(T)$-curve for a field along the $b$-axis of the orthorhombic unit cell.Comment: 6 pages, 5 figures; accepted for publication in Phys. Rev.

A novel non-Fermi-liquid state in the iron-pnictide FeCrAs

We report transport and thermodynamic properties of stoichiometric single crystals of the hexagonal iron-pnictide FeCrAs. The in-plane resistivity shows an unusual "non-metallic" dependence on temperature T, rising continuously with decreasing T from ~ 800 K to below 100 mK. The c-axis resistivity is similar, except for a sharp drop upon entry into an antiferromagnetic state at T_N 125 K. Below 10 K the resistivity follows a non-Fermi-liquid power law, rho(T) = rho_0 - AT^x with x<1, while the specific heat shows Fermi liquid behaviour with a large Sommerfeld coefficient, gamma ~ 30 mJ/mol K^2. The high temperature properties are reminiscent of those of the parent compounds of the new layered iron-pnictide superconductors, however the T -> 0 properties suggest a new class of non-Fermi liquid.Comment: 6 pages, 4 figure

Field-induced nematic-like magnetic transition in an iron pnictide superconductor, Ca10_{10}(Pt3_{3}As8_{8})((Fe1−x_{1-x}Ptx_{x})2_{2}As2_{2})5_{5}

We report a high magnetic field study up to 55 T of the nearly optimally doped iron-pnictide superconductor Ca$_{10}$(Pt$_{3}$As$_{8}$) ((Fe$_{1-x}$Pt$_{x}$)$_{2}$As$_{2}$)$_{5}$ (x=0.078(6)) with a Tc 10 K using magnetic torque, tunnel diode oscillator technique and transport measurements. We determine the superconducting phase diagram, revealing an anisotropy of the irreversibility field up to a factor of 10 near Tc and signatures of multiband superconductivity. Unexpectedly, we find a spin-flop like anomaly in magnetic torque at 22 T, when the magnetic field is applied perpendicular to the ab planes, which becomes significantly more pronounced as the temperature is lowered to 0.33 K. As our superconducting sample lies well outside the antiferromagnetic region of the phase diagram, the observed field-induced transition in torque indicates a spin-flop transition not of long-range ordered moments, but of nematic-like antiferromagnetic fluctuations.Comment: Latex, 4 figure

Reply to Comment by Borisenko et al. on article `A de Haas-van Alphen study of the Fermi surfaces of superconducting LiFeP and LiFeAs'

Recently, Borisenko et al have posted a Comment (arXiv:1108.1159) where they suggest an alternative interpretation of our de Haas-van Alphen (dHvA) measurements on the superconductor LiFeAs. In our original paper (arXiv:1107.4375) we concluded that our measurements of the bulk Fermi surface were not consistent with the surface bands observed thus far by ARPES. Borisenko et al dispute this and suggest the two measurements are consistent if some of the orbits we observe are due to magnetic breakdown. We argue here that this scenario is inconsistent with the experimental data and therefore that our original conclusion stands.Comment: 4 pages with figure

Emergence of the nematic electronic state in FeSe

We present a comprehensive study of the evolution of the nematic electronic structure of FeSe using high resolution angle-resolved photoemission spectroscopy (ARPES), quantum oscillations in the normal state and elastoresistance measurements. Our high resolution ARPES allows us to track the Fermi surface deformation from four-fold to two-fold symmetry across the structural transition at ~87 K which is stabilized as a result of the dramatic splitting of bands associated with dxz and dyz character. The low temperature Fermi surface is that a compensated metal consisting of one hole and two electron bands and is fully determined by combining the knowledge from ARPES and quantum oscillations. A manifestation of the nematic state is the significant increase in the nematic susceptibility as approaching the structural transition that we detect from our elastoresistance measurements on FeSe. The dramatic changes in electronic structure cannot be explained by the small lattice effects and, in the absence of magnetic fluctuations above the structural transition, points clearly towards an electronically driven transition in FeSe stabilized by orbital-charge ordering.Comment: Latex, 8 pages, 4 figure

Hall coefficient anomaly in the low-temperature high-field phase of Sr3Ru2O7

We report a study of the Hall effect of high-purity Sr3Ru2O7 single crystals. We establish an empirical correlation between the onset of its unusual low-temperature, high-field phase and a pronounced dip in the fielddependent Hall coefficient. Unlike the order parameter obtained from measurements of anisotropic resistivity, which is affected by the formation of domains, the Hall effect feature seems to reflect the nature of the ordering within a single domain. We checked for violations of the Onsager relations for the off-diagonal components of the resistivity tensor but do not detect any. We compare our observations to those on materials that have long-wavelength spin structures, and discuss them in relation to a growing body of theoretical work on the nature of the low-temperature phase in Sr3Ru2O7

Quantum oscillations of the magnetic torque in the nodal-line Dirac semimetal ZrSiS

We report a study of quantum oscillations (QO) in the magnetic torque of the nodal-line Dirac semimetal ZrSiS in the magnetic fields up to 35 T and the temperature range from 40 K down to 2 K, enabling high resolution mapping of the Fermi surface (FS) topology in the $k_z=\pi$ (Z-R-A) plane of the first Brillouin zone (FBZ). It is found that the oscillatory part of the measured magnetic torque signal consists of low frequency (LF) contributions (frequencies up to 1000 T) and high frequency (HF) contributions (several clusters of frequencies from 7-22 kT). Increased resolution and angle-resolved measurements allow us to show that the high oscillation frequencies originate from magnetic breakdown (MB) orbits involving clusters of individual $\alpha$ hole and $\beta$ electron pockets from the diamond shaped FS in the Z-R-A plane. Analyzing the HF oscillations we have unequivocally shown that the QO frequency from the dog-bone shaped Fermi pocket ($\beta$ pocket) amounts $\beta=591(15)$ T. Our findings suggest that most of the frequencies in the LF part of QO can also be explained by MB orbits when intraband tunneling in the dog-bone shaped $\beta$ electron pocket is taken into account. Our results give a new understanding of the novel properties of the FS of the nodal-line Dirac semimetal ZrSiS and sister compounds