Strain driven anisotropic magnetoresistance in antiferromagnetic La0.4_{0.4}Sr0.6_{0.6}MnO3_{3}

We investigate the effects of strain on antiferromagntic (AFM) single crystal thin films of La$_{1-x}$Sr$_{x}$MnO$_{3}$ (x = 0.6). Nominally unstrained samples have strong magnetoresistance with anisotropic magnetoresistances (AMR) of up to 8%. Compressive strain suppresses magnetoresistance but generates AMR values of up to 63%. Tensile strain presents the only case of a metal-insulator transition and demonstrates a previously unreported AMR behavior. In all three cases, we find evidence of magnetic ordering and no indication of a global ferromagnetic phase transition. These behaviors are attributed to epitaxy induced changes in orbital occupation driving different magnetic ordering types. Our findings suggest that different AFM ordering types have a profound impact on the AMR magnitude and character.Comment: http://dx.doi.org/10.1063/1.489242

Controlling antiferromagnetic domains in patterned La0.7Sr0.3FeO3 thin films

Transition metal oxide thin films and heterostructures are promising platforms to achieve full control of the antiferromagnetic (AFM) domain structure in patterned features as needed for AFM spintronic devices. In this work, soft x-ray photoemission electron microscopy was utilized to image AFM domains in micromagnets patterned into La0.7Sr0.3FeO3 (LSFO) thin films and La0.7Sr0.3MnO3 (LSMO)/LSFO superlattices. A delicate balance exists between magnetocrystalline anisotropy, shape anisotropy, and exchange interactions such that the AFM domain structure can be controlled using parameters such as LSFO and LSMO layer thickness, micromagnet shape, and temperature. In LSFO thin films, shape anisotropy gains importance only in micromagnets where at least one extended edge is aligned parallel to an AFM easy axis. In contrast, in the limit of ultrathin LSFO layers in the LSMO/LSFO superlattice, shape anisotropy effects dominate such that the AFM spin axes at micromagnet edges can be aligned along any in-plane crystallographic direction

Sugarcane Production, Processing and Marketing in Tanzania

Sugarcane is one of the important food and commercial crops of Tanzania. Its production is concentrated mainly in three regions, Morogoro, Kagera and Kilimanjaro. Most of the sugar produced in the country is for home consumption and only a small proportion is exported to service foreign debts. This paper briefly reviews the agronomic, production and marketing aspects of sugarcane in Tanzania, with special emphasis on the factors associated with variation in production during the past ten years. During the 1983/84 season, the country produced slightly over 130, 000 tons of processed sugar, but 1988/89 production had dropped to just about 96, 000 tons. During the 1990's (1991/92-1993/94), production increased in response to the trade liberalization policy of the country. To increase and sustain the country's future sugar pruduction, improved soil management of sugarcane fields, irrigation technology and the use of improved clones need to be introduced. The current marketing and handling structure in the sugar industry requires reform in order to increase efficiency and reduce storage overheads paid by the consumers

Aerosol radiative forcing over a tropical urban site in India

Using collocated measurements of aerosol radiative properties and radiative fluxes, aerosol radiative forcing is estimated at a tropical urban site in India, located between the sub-continent and the Indian Ocean Experiment [INDOEX] sites. Observed sun/sky radiance data are used to derive aerosol spectral optical depth, single scattering albedo [SSA], asymmetry parameter, precipitable water and total column ozone. These serve as inputs to a radiative transfer model, to estimate aerosol forcing at the surface, the top-of-the atmosphere [TOA] and the atmosphere. During the dry season of 2001 and 2002 [November–April], these were found to be −33, 0 and 33 Wm−2, respectively. Using measured radiative fluxes during different aerosol loading conditions yield a surface forcing of −31 Wm−2. The surface forcing efficiency as computed from the two independent methods is found to be −88 and −84 Wm−2, respectively, while mean SSA at 500 nm is found to be 0.8