Linear magnetoresistivity in the ternary AM2B2 and A3Rh8B6 phases (A = Ca, Sr; M = Rh, Ir)

We studied the magnetoresistivity of the AM2B2 and A3Rh8B6 (A = Ca, Sr; M = Rh, Ir) compounds within the ranges 1.8<=T<=300 K and 0<=H<=50 kOe. The zero-field resistivity {\rho}0(T) is metallic and follows closely the Bloch-Gr\"uneisen description. A positive, nonsaturating, and dominantly linear-in-H magnetoresistivity was observed in all samples, including the ones with a superconducting ground state. Such {\Delta}{\rho}T(H)/{\rho}T(0), reaching 1200% in favorable cases, was found to be much stronger for the AM2B2 compounds and to decrease with temperature as well as when Ca is replaced by Sr, or Rh is replaced by Ir. Finally, the general features of the observed magnetoresistivity will be discussed in terms of the Abrikosov model for the linear magnetoresistivity in inhomogeneous materials.Comment: 6 pages, 8 figure

Resource-Poor Farmers' Constraints regarding Integrated Soil Fertility and Nutrient Management for Sustainable Crop Production: A farm level study in Bangladesh

Sustainable crop production requires a judicious management of soil resources and of all plant nutrient sources available in a farm or a village. The main focus of the study was to determine the constraints faced by the resource-poor farmers regarding integrated soil fertility and nutrient management for sustainable crop production. Field work was conducted in eight villages of four districts in Bangladesh and data were collected from 92 resource-poor farmers through personal interviews. Four point-summated rating scales were used to determine farmers' constraints while five point Likert-type response scales were used to measure the suggestions provided by them to improve the situations. Findings indicated that most of the farmers confronted high problems regarding soil fertility and nutrient management aspects. The issues mostly confronted were the lack of organizing demonstration plots, inadequate training facilities, lack of availability information sources, financial problems, unavailability and unstable price of chemical fertilizers and shortage of knowledge about the beneficial aspect of using organic manure along with chemical fertilizers for crop production. Develop facilities for easy way of getting agricultural loan prior to crop seasons, strengthen extension activities especially for resource-poor farmers, and ensure the availability of chemical fertilizers during cropping seasons with stable price were the matters mostly suggested by farmers to improve the situations.Crop Production/Industries,

Ionic-liquid-gating setup for stable measurements and reduced electronic inhomogeneity at low temperatures

The ionic-liquid-gating technique can be applied to the search for novel physical phenomena at low temperatures because of its wide controllability of the charge carrier density. Ionic-liquid gated field-effect transistors are often fragile upon cooling, however, because of the large difference between the thermal expansion coefficients of frozen ionic liquids and solid target materials. In this paper, we provide a practical technique for setting up ionic-liquid-gated field-effect transistors for low-temperature measurements. It allows stable measurements and reduces the electronic inhomogeneity by reducing the shear strain generated in frozen ionic liquid.Comment: 5 pages, 6 figure

Diamond anvil cell using boron-doped diamond electrodes covered with undoped diamond insulating layer

Diamond anvil cell using boron-doped metallic diamond electrodes covered with undoped diamond insulating layer have been developed for electrical transport measurements under high pressure. These designed diamonds were grown on a bottom diamond anvil via a nanofabrication process combining microwave plasma-assisted chemical vapor deposition and electron beam lithography. The resistance measurements of high quality FeSe superconducting single crystal under high pressure were successfully demonstrated by just putting the sample and gasket on the bottom diamond anvil directly. The superconducting transition temperature of FeSe single crystal was enhanced up to 43 K by applying uniaxial-like pressure