RESUMO
In this communication, structural, microstructural, transport and magnetotransport properties are reported for La0.7Pb0.3MnO3/LaAlO3 (LPMO/LAO) manganite films having different thicknesses. All the films were irradiated with 200 MeV Ag+15 swift heavy ions (SHI). Films were grown using the sol-gel method by employing the acetate precursor route. Structural measurements were carried out using the X-ray diffraction (XRD) method at room temperature, while atomic force microscopy (AFM) was performed for the surface morphology. Temperature dependent resistivity under different applied magnetic fields for all the films shows metal to insulator transition at temperature TP. In addition to the metal to insulator transition at TP, the films also exhibit low temperature resistivity upturn behavior. Resistivity, TP and upturn behavior are highly influenced by the film thickness, applied magnetic field and irradiation. To understand the nature of charge transport for the low temperature resistivity behavior and metallic and insulating (semiconducting) regions, various models and mechanisms have been verified and the most suitable mechanism has been found for each region in the resistivity curves. Magnetoresistance (MR) is affected by temperature, film thickness and irradiation. MR behavior has been understood in terms of combined and separate contributions from grains and grain boundaries in the films.
RESUMO
Correction for 'Charge transport mechanisms in sol-gel grown La0.7Pb0.3MnO3/LaAlO3 manganite films' by Eesh Vaghela et al., Phys. Chem. Chem. Phys., 2017, DOI: 10.1039/c6cp07730g.
RESUMO
Both Ba4Mn3O10 and Sr4Mn3O10 crystallize in an orthorhombic crystal structure consisting of corrugated layers containing Mn3O12 polydedra. The thermal variation of magnetic susceptibility of the compositions consists of a broad hump like feature indicating the presence of low dimensional magnetic correlation. We have systematically investigated the magnetic data of these compounds and found that the experimental results match quite well with the two dimensional Heisenberg model of spin-spin interaction. The two dimensional nature of the magnetic spin-spin interaction is supported by the low temperature heat capacity data of Ba4Mn3O10. Interestingly, both the samples show dielectric anomaly near the magnetic ordering temperature indicating multiferroic behavior.
RESUMO
Unfreedom in Indian agriculture is ordinarily associated with adult male bonded labour, and it is generally argued that unfreedom is likely to disappear as capitalism spreads/advances. By contrast, we find that workers employed on advanced capitalist cotton seed farms in Andhra Pradesh - accumulation linked to national and multinational capital - involves the employment of labour-power which is mostly unfree, female and young (7-14 years). Addressed here are the reasons for the transformations in the age and gender of unfree workers on such farms since the early 1970s. We argue that, in the context of men's emancipation from bonded labour, employers actively sought out relatively cheaper, more easily disciplined, unfree female labour. Then, in order to secure even cheaper female child labour, employers segmented the female labour market via ideologies about the superiority of female children over adult females. Corresponding changes in labourers' gender relations, which put more of the onus of family maintenance on to women and daughters, were found to facilitate the unfreedom of females.
