Influence of the interface morphology on the magnetization of Magnetic/Non-Magnetic (Fe/Cu) multilayers: a Monte Carlo investigation

A Monte Carlo investigation was used to study the magnetization of a Heisenberg multilayers system. Our model consists of an alternate staking of Magnetic and Non-Magnetic layers (M/NM) with disordered interfaces. The results indicate that the magnetization of multilayers M/NM depends on the atomic composition, the interface morphology and the exchange interactions at the interface.A Monte Carlo investigation was used to study the magnetization of a Heisenberg multilayers system. Our model consists of an alternate staking of Magnetic and Non-Magnetic layers (M/NM) with disordered interfaces. The results indicate that the magnetization of multilayers M/NM depends on the atomic composition, the interface morphology and the exchange interactions at the interface

Mössbauer study and Monte Carlo simulations of the hyperfine field distribution in Magnetic/Non-Magnetic (M/NM) multilayers

Using a Monte Carlo numerical method, we perform a complementary analysis of the hyperfine field distribution in Magnetic/Non-Magnetic (M=Fe/NM=Cu) multilayers and a comparison with Mössbauer experiment results of [Fe(40)=Cu(20)]20 multilayers. From differing relaxation rates for spins with few near neighbor spins and particularly those located at the interface, the Mössbauer result can be simulated. Our model consists of an alternate stacking of magnetic and non-magnetic layers (MnM/NMnNM) with disordered interface. The simulation results confirm that the concentration of interface alloys (M1-xNMx) and magnetic layer thickness modify systemically the magnetization distribution in the M/NM multilayers. The result is in agreement with Mössbauer experimental analysis

Yield gaps and nutrients use efficiency of apple tree (golden delicious/MM106) in the middle Atlas Mountains of Morocco

The main objective of this work was to evaluate use efficiency of nitrogen, phosphorus, potassium, calcium and magnesium in adult apple orchards in the Middle Atlas of Morocco and to establish preliminary reference norms for fertilizing this crop under local conditions. The study was based on soil and leaf analysis and data with regard to farming practices and yield on forty apple orchards (cv. Golden delecious/MM106) where nineteen are growing on silty-clay soil and twenty-one on sandy-loam soil. The results showed significant correlations between leaf content for each nutrient and yield level following polynomial equations, thereby indicating local reference norms for apple leaf analysis. Moreover, correlations were significant between leaf and soil contents that permitted to determine apple needs in nitrogen fertilizer and references norms for soil richness in phosphorus, potassium, calcium and magnesium to obtain yield potential in the study region. However, the found norms are less than International standards because of feebleness of yield level in the study region, largely related to deficient cultural practices adopted by farmers. In addition, investigation of leaf nutrients ratios N/K, N/Ca, K/Ca, K/Mg and Ca/Mg showed that there was disharmony in uptake of these nutrients originating particularly from high soil richness in Ca and Mg. Taking into account these considerations, the found references norms can be applied only under the adopted farming practices. Nevertheless, by improving local practices, reference values may change

Prévision de l'évolution de l'évapotranspiration de référence sous l'impact du changement climatique dans la province d'Ifrane (Maroc)

Climate change presents new challenges for agriculture. When it comes to planning adaptation measures, estimating the crop water requirement plays a key role. In the water cycle, evapotranspiration accounts for around two-thirds of the volume of exchanges, and its estimation is important for irrigation scheduling, water resources planning and management. The reference evapotranspiration (ET0) defines the potential evaporation of a standard vegetation cover with plenty of water. It is calculated using several models, including that of Jensen and Haise, used in this study to predict the evolution of the ET0 by 2050 in the province of Ifrane (NW Morocco). To do this, the current and future monthly mean air temperature from the Miroc-ESM model and according to two climatic scenarios RCP4.5 and RCP8.5, were downloaded from Worlclim database. Personalized climatic layers of the study area are generated using the two software DIVA-GIS and ArcGIS. The results show that the ET0 will increase in the future for all months and more markedly for pessimistic scenario RCP8.5, it will vary between 9 mm in January and December and 135 mm in July for the RCP8.5 scenario and between 8 mm in January and 131 mm in July for RCP4.5 scenario, against 4 mm in January and 118 mm in July currently. This highlights the need for adaptation of agriculture in the study area by mastering the opportunities and risks of climate change concerning water resources.Le changement climatique place l’agriculture face à de nouveaux défis. Lorsqu’il s’agit de planifier les mesures d’adaptation, l’estimation du besoin en eau des cultures joue un rôle capital. Dans le cycle de l'eau, l’évapotranspiration représente de l’ordre des deux tiers du volume des échanges et son estimation est importante pour les programmes d'irrigation, la planification et la gestion des ressources en eau. L’évapotranspiration de référence définit le potentiel d’évaporation d’un couvert végétal standard abondamment approvisionné en eau. Elle se calcule à l'aide de plusieurs modèles, parmi lesquels celui de Jensen et Haise, utilisé dans cette étude pour prévoir l'évolution de l'évapotranspiration de référence à l'horizon 2050 dans la province d'Ifrane, pour ce faire, des données climatiques de la température moyenne mensuelle actuelle et future selon deux scénarios climatiques RCP8.5 et RCP4.5, ont été téléchargées des bases de données climatiques pour le modèle climatique Miroc-ESM. Les résultats montrent que l'ET0 augmentera dans le futur et d'une façon plus marquée pour le scénario pessimiste Rcp8.5, elle variera entre 9 mm en janvier et décembre et 135 mm au mois de juillet pour le scénario RCP8.5 et entre 8 mm en janvier et 131 mm en juillet pour le scénario RCP4.5 contre 4 mm en janvier et 118 mm au mois de juillet actuellement. Ce qui met en évidence la nécessité d’adaptation de l'agriculture dans la zone d'étude en maitrisant les opportunités et les risques du changement climatique concernant la ressource en eau

Bethe lattice approach study of the mixed spin-1/2 and spin-7/2 Ising model in a longitudinal magnetic field

The magnetic properties of the mixed spin-1/2 and spin-7/2 Ising model with a crystal-field in a longitudinal magnetic field are investigated on the Bethe lattice using exact recursion relations. The ground-state phase diagram is constructed. The temperature-dependent one is displayed in the case of uniform crystal-field on the (k_BT/|J|, D/|J|) plane in the absence of the external constraint for lattice coordination numbers z=3,4,6. The order parameters and corresponding response functions as well as the internal energy are calculated and examined in detail in order to feature the real nature of phase boundaries and corresponding temperatures. The thermal variations of the average magnetization are classified according to the Néel nomenclature

Structural, magnetic and magnetocaloric study of Ni0.5Zn0.5Fe2O4 spinel

International audienc

Substitutional effect of Mg2+ on structural and magnetic properties of cobalt nanoferrite

International audienc