Underdevelopment and class-formation: The origins of migrant labour in Namibia, 1850-1915

African Studies Seminar series. Paper presented September 1975In Namibia the evolution of the principal stages of colonial exploitation was telescoped into a 2O-year period under German rule. Only in the 1890s was over, half a century of "informal colonialism", whose chief agents were intinerant traders and missionaries, reinforced by German military intervention. Yet by the outbreak of the Great War, most of the land in southern and central Namibia had been expropriated, some of it already settled with immigrant farmers, internal resistance crushed, and the Namib diamond deposits and Tsumeb copper, today still the territory's main mineral resources, put into full production by international mining capital. None of the sectors of capital which developed during this period had more than a marginal interest in the human resources of the country except as labour-power; and its recruitment, distribution and control was from the start a principal function of colonial administration. However, because of the particular historical conditions of that first phase of colonialisation, the forcible separation of subsistence agriculturalists from their means of production was never completed; and the level of recruitment from the ranks of the dispossessed consistently failed to meet the aggregate labour demand of colonial capital. The closing of this gap with contracted migrant labour, and the latter's long-term reproduction, was therefore the central motive for the conservation of the remaining areas of subsistence production by both German and South African administrations. It is with this section of the Namibian working class that I am concerned in this paper

Electron transfer and spin injection in C60-ferromagnetic composites

The magnetic properties of spin doped fullerenes are investigated in hybrid organic/inorganic structures with the aim of establishing the extent to which magnetic states can be induced and controlled in these materials. Volume magnetometry is used to measure a reduction of net magnetization and an increase in coercivity in cobalt which can be understood in terms of a transfer of majority spin electrons from the transition metal d-band into spin polarized hybrid interface states. This is supported by PNR and XAS studies of Co/C60 which reveal AF coupling between Co metal films and a hybrid interfacial region where magnetic ground states are induced in fullerenes through charge transfer. Investigations of hybridization between C60 and the RE-TM alloy CoGd show that the compensation temperature of the ferrimagnet is altered by the presence of C60. PNR measurements of CoGd/C60 MLs reveal interfacial coupling which creates an AF region 1.5 $\pm$ 0.1 nm thick. Magnetometry of Gd/C60 bilayers indicates that hybridization between the metal conduction bands and the C60 LUMO modifies magnetic ordering in Gd. This is supported by the observation of novel features in the temperature dependence of magnetization and resistivity in the composite. XAS of Gd/C60 bilayers shows a large peak in the carbon K-edge at 282 eV which is attributed to interfacial hybridization. It is shown that PL quenching in C60 is greater over Co than Au which is attributed to the greater electron transfer between Co and C60. PL quenching is proposed as an effective way to measure magnetic coupling and electron transfer in interfaces. Raman spectra are recorded in C60 junctions during spin polarised transport. The Ag(2) peak splitting is shown to depend on the polarisation of injected current acting as an effective probe of triplet formation in C60. Finally, XAS at the carbon K-edge is recorded during spin transport. A suppression of the LUMO to zero and increase in the intensity of the 282 eV peak occurs after removal of external bias and is shown to be reversible and repeatable under cycles of grounding and charge injection. A proposed mechanism involving the redistribution of charge following the removal of bias which causes electrons to become trapped in interfacial states is suggested

Growth of crystalline C₆₀ by evaporation

This application note describes the growth of crystalline thin films of C6

Reimagining agricultural development pathways in Malawi through participatory video

Hierarchical top-down approaches to agricultural development, based predominantly on neoliberal priorities, supported by materialistic philosophies and positivist evidence bases, dominate agricultural development chains, squeezing out space for alternatives to exist, let alone thrive. Participatory approaches to research and development were initially conceived as ways to break out of top-down development chains. Yet over time they have been sucked in to materialistic and neoliberal pathways and in the process have become tools for the tokenistic involvement and/or manipulation of rural Malawians, whose perspectives continue to go unseen and unheard. This investigation took the stance that genuine participatory research is still possible if space is systematically made for participants to take control and work with researchers/facilitators in processes of reflection and open communication. Participatory video (PV) in particular can provide platforms for participants to be seen and heard as they produce a film, or films, which can be shared with diverse audiences. A thorough mixed method approach based on 87 semi-structured interviews, followed by a five month PV process in one case study location, including 16 workshops and a further 6 weeks of editing, led to a participatory film entitled Tigwirane Manja (Holding Hands), which was screened 9 times to diverse audiences. This extensive process provided the means to explore the potential of genuine participatory research using PV and created space to reimagine agricultural development in Malawi

Towards self-discovery: Elucidating adolescent intra-psychic tensions

In this research piece I set out to shed light on narratives of recovery from adolescent depression. I interview ten adults in their twenties, both male and female who deem themselves to have recovered from adolescent depression, and I analyse their stories from the perspective of Narrative Oriented Inquiry (Hiles & Cermak, 2008). A full picture emerges of individuals who have come to make sense of their experiences of teenage depression by casting their recovery in terms of processes of self-discovery. I specify that participants universally evoke a sense of themselves as being composed of various constituent "parts". Recovery, for participants, involves a redefinition of how one relates to one's vulnerable parts within the context of a multifaceted sense of identity. I conclude the research by situating this finding in its socio-cultural context and by relating it to existing theory pertaining to the phenomenon of multiplicity of mind

Van der Waals epitaxy of C₆₀ on the topological insulator Bi₂Se₃

This application note describes the growth of a novel Bi₂Se₃/ C₆₀ heterostructure in the Royce deposition system at the University of Leeds. We also present structural characterisation and transmission electron microscopy data in order to understand nature of the Bi₂Se₃/ C₆₀ interface

Optical conversion of pure spin currents in hybrid molecular devices

Carbon-based molecules offer unparalleled potential for THz and optical devices controlled by pure spin currents: a low-dissipation flow of electronic spins with no net charge displacement. However, the research so far has been focused on the electrical conversion of the spin imbalance, where molecular materials are used to mimic their crystalline counterparts. Here, we use spin currents to access the molecular dynamics and optical properties of a fullerene layer. The spin mixing conductance across Py/C60 interfaces is increased by 10% (5 × 1018 m−2) under optical irradiation. Measurements show up to a 30% higher light absorbance and a factor of 2 larger photoemission during spin pumping. We also observe a 0.15 THz slowdown and a narrowing of the vibrational peaks. The effects are attributed to changes in the non-radiative damping and energy transfer. This opens new research paths in hybrid magneto-molecular optoelectronics, and the optical detection of spin physics in these materials

π-anisotropy: A nanocarbon route to hard magnetism

High coercivity magnets are an important resource for renewable energy, electric vehicles, and memory technologies. Most hard magnetic materials incorporate rare earths such as neodymium and samarium, but concerns about the environmental impact and supply stability of these materials are prompting research into alternatives. Here, we present a hybrid bilayer of cobalt and the nanocarbon molecule C60 which exhibits significantly enhanced coercivity with minimal reduction in magnetization. We demonstrate how this anisotropy enhancing effect cannot be described by existing models of molecule-metal magnetic interfaces. We outline a form of anisotropy, arising from asymmetric magnetoelectric coupling in the metal-molecule interface. Because this phenomenon arises from π−d hybrid orbitals, we propose calling this effect π-anisotropy. While the critical temperature of this effect is currently limited by the rotational degree of freedom of the chosen molecule, C60, we describe how surface functionalization would allow for the design of room-temperature, carbon-based hard magnetic films

Observation of a molecular muonium polaron and its application to probing magnetic and electronic states

We thank the Engineering and Physical Sciences Research Council (EPSRC UK) for support via Grants No. EP/M000923/1, No. EP/K036408/1, No. EP/I004483/1, No. EP/S031081/1, and No. EP/S030263/1. L.L., S.S., D.J. and G.T. acknowledge also support from STFC-ISIS Neutron and Muon Source and Ada Lovelace Centre at STFC-SCD. We acknowledge use of the ARCHER (via the U.K. Car–Parrinello Consortium, EP/P022618/1 and EP/P022189/2), U.K. Materials and Molecular Modelling Hub (EP/P020194/1), and STFC Scientific Computing Department's SCARF HCP facilities. We acknowledge support from the Henry Royce Institute. This work was also supported financially through the EPSRC Grant Nos. EP/ P022464/1, and EP/R00661X/1.Muonium is a combination of first- and second-generation matter formed by the electrostatic interaction between an electron and an antimuon (μ+). Although a well-known physical system, their ability to form collective excitations in molecules had not been observed. Here, we give evidence for the detection of a muonium state that propagates in a molecular semiconductor lattice via thermally activated dynamics: a muonium polaron. By measuring the temperature dependence of the depolarization of the muonium state in C60, we observe a thermal narrowing of the hyperfine distribution that we attribute to the dynamics of the muonium between molecular sites. As a result of the time scale for muonium decay, the energies involved, charge and spin selectivity, this quasiparticle is a widely applicable experimental tool. It is an excellent probe of emerging electronic, dynamic, and magnetic states at interfaces and in low dimensional systems, where direct spatial probing is an experimental challenge owing to the buried interface, nanoscale elements providing the functionality localization and small magnitude of the effects.Publisher PDFPeer reviewe