Synthesis and characterization of single phase Mn doped ZnO

Different samples of Zn1-xMnxO series have been prepared by conventional solid state sintering method. It has been identified, up to what extent of doping enable us to synthesize single-phase polycrystalline Mn doped ZnO samples which is one of the prerequisite for dilute magnetic semiconductor and we have analyzed its certain other physical aspects. In synthesizing the samples proportion of Mn varies from 1 at% to 5 at%. However the milling times have been varied (6, 12, 24, 48 & 96 hours) for only 2 at% Mn doped samples while for other samples (1, 3, 4 & 5 at% Mn doped) the milling time has been kept fixed at 96 hours. Room temperature X-Ray diffraction (XRD) data reveal that all of the prepared samples up to 3 at% of Mn doping exhibit wurtzite-type structure, no segregation of Mn and/or its oxides has been found. The 4 at% Mn doped samples show a weak peak of ZnMn2O4 apart from usual other peaks of ZnO and the intensity of this impurity peak has been further increased for 5 at% of Mn doping. So beyond 3 at% doping single-phase behavior is destroyed. Band gap for all the 2 at% Mn doped samples have been estimated as between 3.21 to 3.19 eV and reason for this low band gap values has been explained through the grain boundary trapping model. The room temperature resistivity measurement shows increase of resistivity up to 48 hours of milling and with further milling it saturates. The defect state of these samples has been investigated by using positron annihilation lifetime (PAL) spectroscopy technique. Here all the relevant lifetime parameters of positron i.e. free annihilation (tau 1), at defect site (tau 2) and average (tau av) increases with milling time.Comment: 26 pages, 7 figures; Submitted to Physica B after minor correctio

Requirements of Business Judgment Rule and Their Effect on the Practical Use of the Rule

Pravilo poslovne presoje ima v Združenih državah Amerike že dolgo tradicijo, v evropskih državah s kontinentalnimi pravnimi sistemi pa so se ga sodišča pri presoji poslovnih odločitev članov organov vodenja in nadzora začela posluževati šele v zadnjih desetletjih. Slovenija je ena izmed vse manjše skupine držav, ki pravila poslovne presoje in njihovih kriterijev še ni prenesla iz sodne prakse v zakonodajo. Pravilo poslovne presoje omogoča sodiščem, da pri presoji, ali so člani organov vodenja in nadzora odškodninsko odgovorni za družbi škodljive odločitve, s pomočjo upoštevanja kriterijev pravila prilagodijo presojo specifičnemu položaju tožencev. Magistrska naloga z namenom iskanja bistva in praktičnega pomena kriterijev pravila poslovne presoje najprej pojasni pojem korporacijskega upravljanja in dinamiko akterjev v delovanju gospodarskih družb. Po kratki naslovitvi dolžnosti članov organov vodenja in nadzora tako v našem pravu kot v pravu tujih držav sledi pregled razvoja kriterijev pravila skozi sodno prakso v njegovem domicilu, Združenih državah Amerike. Kratko so predstavljene različne variacije pravila poslovne presoje v različnih zakonodajnih in kvazizakonodajnih aktih ter pojasnjeni razlogi za njegove pojavne oblike, ki jih v največji meri zaznamujejo različna razumevanja njegovega namena. Sledi podrobna obravnava posameznih kriterijev pravila od prve omembe do sodobne interpretacije, z ozirom na način njegove razlage v slovenski teoriji in praksi. Dilema (ne)pravilnosti slovenske percepcije pravila poslovne presoje se prevesi v zaključni sklep, ki predvsem poudarja pomen prostega polja presoje, ki ga sodiščem omogoča določena mera nedoločenosti kriterijev.Although business judgment rule has a long tradition in the United States of America, the courts in European countries with continental legal systems have only started to use it in the last decades for dealing with business decisions of management. Slovenia is one of the shrinking group of countries that has not yet transferred the rule from case law to law in books. Business judgment rule enables the courts to make use of requirements of the rule in order to properly adjust the judicial decision whether board members are liable for business decisions that resulted in losses for the company. In pursuit of finding the core purpose and practical contribution of requirements of the rule, this master\u27s thesis first explains the concept of corporate governance and dynamics among the different subjects in the company\u27s framework. After a brief mention of management\u27s duties in Slovenian law as well as the law in other countries, thesis continues with an overview of development of the rule\u27s requirements in the rule\u27s cradle, the United States of America. Following is the presentation of different varieties of business judgment rule in different legislative and quasi-legislative acts and the clarification of reasons for so many variations of the rule, which are shaped mostly by different understandings of its core purpose. Detailed explanation of each individual requirement is next, from its first mentions in case law to its modern interpretation with respect to the way each requirement is interpreted in Slovenian case law. The question of suitability of the Slovenian perception of business judgment rule is followed by final conclusion which emphasizes the importance of discretion field the rule\u27s requirements create if they are, to the certain extent, undetermined

Competing anisotropies in bcc Fe81Ni19/Co(001) superlattices

Contains fulltext : 75351.pdf (publisher's version ) (Open Access)3 p

Magnetic anisotropy and evolution of ground-state domain structures in bcc Fe81Ni19/Co(001) superlattices

Contains fulltext : 71918.pdf (publisher's version ) (Open Access)15 p

Magnetocaloric effect in Fe2P: Magnetic and phonon degrees of freedom

Contains fulltext : 212412.pdf (publisher's version ) (Open Access

Effects of strain on ferroelectric polarization and magnetism in orthorhombic HoMnO3

We explore how the ferroelectric polarization of antiferromagnetic E-type orthorhombic HoMnO3 can be increased, by investigating the effects of in-plane strain on both the magnetic properties and the ferroelectric polarization, using combined density functional theory calculations and a model Hamiltonian technique. Our results show that the net polarization is strongly enhanced under compressive strain, due to an increase of the electronic contribution to the polarization. In contrast, the ionic contribution is found to decrease. We identify the electron-lattice coupling, due to Jahn-Teller (JT) distortions, and its response to strain, to be responsible for the observed behavior. The JT-induced orbital ordering of occupied Mn-e(g)(1) electrons in alternating 3x(2)-r(2)/3y(2)-r(2) orbital states in the unstrained structure, changes under in-plane compressive strain to a mixture with x(2)-z(2)/y(2)-Z(2) states. The asymmetric hopping of e(g) electrons between Mn ions along zigzag spin chains (typical of the AFM-E spin configuration) is therefore enhanced under strain, explaining the large value of the polarization. Using a degenerate double-exchange model including electron-phonon interaction, we reproduce the change in the orbital ordering pattern. In this picture, the orbital ordering change is related to a change of the Berry phase of the e(g) electrons. This causes an increase of the electronic contribution to the polarization. DOI: 10.1103/PhysRevB.87.014403 RI Barone, Paolo/C-8918-201