Changes in soil organic C (C org ), total N (N t ), available nutrients, soil microbial biomass C (C mic ) and N (N mic ), and mineralizable C and N in the sugarcane (Saccharum officinarum L.) rhizosphere were evaluated under intensive sugarcane cropping systems with intercrops including wheat (Triticum aestivum L.), maize (Zea mays L.), rajmash (Phaseolus vulgaris L.), green gram [Vigna radiata (L.) R. Wilczek var. radiata], cowpea [Vign aunguiculata (L.) Walp.], lentil (Lens culinaris Medik.), mustard (Brassica rapa L.), potato (Solanum tuberosum L.), and sesbania (Sesbania rostrata Bremek. & Oberm.) in subtropical soils of India. Organic C increased significantly when maize (25%), wheat (24%), mustard (19%), potato (17%), and rajmash (13%) were intercropped with sugarcane, while legume intercrops substantially increased N t and available N. Increase in microbial respiration was greater where maize (42%), wheat (37%), or mustard (31%) were intercropped compared with pulse crops. Soil microbial biomass C accounted for 2.7 to 3.3% of C org content and N mic accounted for 2.6 to 3.7% of N t under different intercropping conditions. A higher CO 2 evolution rate and wider C mic /N mic ratios were recorded with cereal and mustard intercrops, whereas higher N mineralization was recorded with pulse intercrops. Results indicate that intercropping with pulse crops and incorporation of their labile C substrate improved N mineralization. The build up of the C pool and C mic in the case of cereals, mustard, and potato intercropping should promote longterm stability.

Summary Two populations of Agrostis stolonifera and seven populations of Festuca rubra from salt marsh and inland habitats were grown on a free draining soil and at two levels of soil waterlogging. The growth of A. stolonifera was stimulated by soil waterlogging while that of F. rubra was depressed. There was no difference between the two populations of A. stolonifera in growth response to waterlogging but the inland population had a greater Fe concentration in the shoots when grown on waterlogged soil than the salt marsh population. In F. rubra the yield of the salt marsh populations was generally less depressed by soil waterlogging than that of populations from free draining soils; the salt marsh populations also had lower concentrations of Fe and Mn in the shoot on the continuously waterlogged soil than the inland populations. It is concluded that the evolution of a degree of waterlogging tolerance has occurred in the salt marsh populations of F. rubra in response to the periodic flooding by sea water in their native habitats.

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Perpendicular magnetic anisotropy (PMA) and low magnetic damping are the key factors for the free layer magnetization switching by spin transfer torque technique in magnetic tunnel junction devices. The magnetization precessional dynamics in soft ferromagnetic FeTaC thin film with a stripe domain structure was explored in broad band frequency range by employing micro-strip ferromagnetic resonance technique. The polar angular variation of resonance field and linewidth at different frequencies have been analyzed numerically using Landau-Lifshitz-Gilbert equation by taking into account the total free energy density of the film. The numerically estimated parameters Landé g-factor, PMA constant, and effective magnetization are found to be 2.1, 2×10 5 erg/cm 3 and 7145 Oe, respectively. The frequency dependence of Gilbert damping parameter (α) is evaluated by considering both intrinsic and extrinsic effects into the total linewidth analysis. The value of α is found to be 0.006 at 10 GHz and it increases with decreasing precessional frequency.Spin transfer torque (STT) has grater credibility compared to other techniques towards ultrafast spin dynamics in ferromagnet by electric current induced magnetization reversal of spin valves and magnetic tunnel junctions (MTJ). 1 The current researchers are more keen to focus on STT technology for its high density magnetic random access memories (MRAM), 2,3 STT-driven domain wall devices 4 and perpendicular magnetic recording media 5 applications. In order to make this technology more efficient, lowering the critical current density is essential which requires the material specifications with low saturation magnetization (M S ), high spin polarization, large uniaxial perpendicular magnetic anisotropy (PMA) constant and low magnetic damping. [6][7][8] The magnetic damping parameter (α) can be described well by the phenomenological Landau-Lifshitz-Gilbert equation and is known as the Gilbert damping. 9,10 Several attempts have been made for understanding the origin of Gilbert damping in spin dynamics relaxation in single layer as well as multilayered magnetic alloys, which arises from both intrinsic and extrinsic parts of the material. The intrinsic contribution to the Gilbert damping parameter has been studied by tuning the strength of the spin-orbit coupling. 8,11,12 Recently, Ikeda et al. 13 have reported that CoFeB-MgO based MTJ with PMA would be reliable for high-density non-volatile memory application due to its high thermal stability and efficiency towards STT technology. The investigation on magnetic dynamics, PMA and the apparent magnetic damping have been studied extensively in CoFeB based soft ferromagnetic thin film by ferromagnetic resonance (FMR) and timeresolved magneto-optical Kerr effect. 14,15 Malinowski et al. 16 have reported a large increase in Gilbert damping with applied magnetic field in perpendicularly magnetized CoFeB thin film.

We report on the study of thickness and temperature dependent magnetic properties of amorphous FeTaC (t = 20–200 nm) thin films prepared on thermally oxidized Si substrate at ambient temperature. Room temperature coercivity remains constant (∼1.5 Oe) for t between 20 and 50 nm, but increases rapidly (>18 Oe) when t > 50 nm. Also, the shape of M-H loop changes from rectangular to flat loop with increasing film thickness; and at larger thicknesses (>50 nm), the central range of constant slope in the flat loop extended largely along with the enlargement of hysteresis around the origin. This is mainly due to the development of perpendicular anisotropy with increasing the film thickness causing a transition from in-plane orientations of the spins to a magnetic stripe domain structure, which degrades the magnetic properties at larger thickness. Low temperature thermomagnetization curves obtained under zero-field-cooled (ZFC) and field-cooled (FC) conditions depicts a bifurcation between ZFC and FC data at larger thickness films. With decreasing t, the bifurcation point shifted to lower temperatures and almost disappeared for t ≤ 50 nm. On the other hand, the high temperature magnetization data reveal a considerable increase in Curie temperature with decreasing film thickness and the magnetic susceptibility critical exponent γ exhibits a thickness dependent behavior. The observed results are discussed on the basis of two-layer model, and the development of perpendicular anisotropy and magnetic disorder with increasing FeTaC film thickness.