Strong electronic correlation and strain effects at the interfaces between polar and nonpolar complex oxides

The interface between the polar LaAlO$_3$ and nonpolar SrTiO$_3$ layers has been shown to exhibit various electronic and magnetic phases such as two dimensional electron gas, superconductivity, magnetism and electronic phase separation. These rich phases are expected due to the strong interplay between charge, spin and orbital degree of freedom at the interface between these complex oxides, leading to the electronic reconstruction in this system. However, until now all of these new properties have been studied extensively based on the interfaces which involve a polar LaAlO$_3$ layer. To investigate the role of the A and B cationic sites of the ABO$_3$ polar layer, here we study various combinations of polar/nonpolar oxide (NdAlO$_3$/SrTiO$_3$, PrAlO$_3$/SrTiO$_3$ and NdGaO$_3$/SrTiO$_3$) interfaces which are similar in nature to LaAlO$_3$/SrTiO$_3$ interface. Our results show that all of these new interfaces can also produce 2DEG at their interfaces, supporting the idea that the electronic reconstruction is the driving mechanism for the creation of the 2DEG at these oxide interfaces. Furthermore, the electrical properties of these interfaces are shown to be strongly governed by the interface strain and strong correlation effects provided by the polar layers. Our observations may provide a novel approach to further tune the properties of the 2DEG at the selected polar/nonpolar oxide interfaces.Comment: 5 pages, 4 figure

Validitas Lembar Kerja Peserta Didik Berbasis Penemuan Terbimbing dalam Upaya Meningkatkan Pemahaman Konsep dan Kemampuan Penalaran Matematis

Learning equipment is important things that determine the quality of the learning process and output. We need a study about validity, practicality, and effectiveness of the learning equipment to ensure teaching and learning quality. The purpose of this research is to evaluate the validity of the learning equipment based on guided discovery, especially the students' worksheets. This research was a descriptive qualitative research that provides the result of students' worksheets and experts recommendation. The experts who validated these student's worksheets were three experts on mathematics education. The instruments used in this study was the validation sheets for LKPD. The result of validation sheets analysis for LKPD showed that in general, the students' worksheets were valid. The validity of the didactical aspect and contents aspect sequently were 0,667 dan 0,704. &nbsp

GEOGRAPHIC INFORMATION SYSTEM OF CROPS

Crops is one of agriculture part will be needed in the lives of human being. Food is a basic requirement for humans to be able to maintain life and hence the adequacy of food for every person at all times. Food security is a condition where the availability of food is sufficient for their food needs. It will continue to maintain the sustainability of food consumption and also help balance a fluctuation in prices and production of crops. Food availability is one aspect that exists in food security that is intended to fulfill a food need. Food security have several aspects, such as food availability, coverage, stability and quality of consumption. Mapping food security using Geographic Information System is important, by knowing the situation of food in the region, both the government and other institutions can make policies that are right on target. The objective of research will make a geographic information system related to food crop mapping to pay attention conditions of food security and can see the potential of food crop production from a sub-district that have high productivity especially for rice, cassava, sweet potato, soybean

Studi Eksperimental Nanorefrigeran Tio2-r600a Sebagai Refrigeran Masa Depan

The use of CFC refrigerants (Chloro Fluoro Carbon) leads to destruction of ozone layer and global warming. An alternative refrigerant is hydrocarbon refrigerant, but it has the disadvantage of easily exploded. This experimental study has been conducted to study the effect of addition of TiO2, which are flame retardant, on the performance of hydrocarbon refrigerant R600a (nanorefrigeran TiO2-R600a). Test of Performance conducted according to refrigerants national standards IEC 60335-2-24-2010. The result is R600a-TiO2 is safe and efficient to be used as a refrigerant without any modification on refrigerator. TiO2 increases the thermal conductivity and heat transfer of refrigerant. The best performance is obtained at TiO2 concentration of 1 g / L (COP = 4,821). It is expected that the nanorefrigeran TiO2-R600a can be used as the primary refrigerant in the future that are environmentally friendly and efficient