Y(Ni, Mn)O3 epitaxial thin films prepared by pulsed laser deposition

High–quality epitaxial YNixMn1-xO3 thin films have been successfully grown on SrTiO3 (100) (STO) by pulsed laser deposition. X-ray diffraction studies showed that the films deposited on STO are fully c-axis oriented and exhibit in-plane alignment. The magnetic transition temperatures (Tc) of the films (both x=0.33 and 0.5) are equivalent to the values of the corresponding bulk samples. However, when x=0.5, the films show magnetic properties quite different from those of bulk samples. This difference may be caused by the structure distortion in these films.Comment: 14 pages, 4 figures. to be publishe

Hall Resistivity in Ferromagnetic Manganese-Oxide Compounds

Temperature-dependence and magnetic field-dependence of the Hall effect and the magnetic property in manganese-oxide thin films are studied. The spontaneous magnetization and the Hall resistivity are obtained for a various of magnetic fields over all the temperature. It is shown that the Hall resistivity in small magnetic field is to exhibit maximum near the Curie point, and strong magnetic field moves the position of the Hall resistivity peak to much high temperature and suppresses the peak value. The change of the Hall resistance in strong magnetic field may be larger than that of the diagonal ones. The abnormal Hall resistivity in the ferromagnetic manganese-oxide thin-films is attributed to the spin-correlation fluctuation scattering.Comment: Latex, 2 Figures, 10 Page

Perspektivenreflexives Sprechen über Interkulturalität

Dem Begriff Interkulturalität wird vorgeworfen, dass er eine raum-zeitliche Abgrenzbarkeit von Kulturen impliziere und die kulturelle Durchmischung moderner Gesellschaften nicht ausreichend berücksichtige. Diese Kritik scheint besonders vor dem Hintergrund der in der letzten Zeit sprunghaft angestiegenen Migrationsbewegungen an Aktualität zu gewinnen. Ist der Begriff also obsolet geworden oder müssen wir ihn neu denken? Der Artikel spricht sich dafür aus, den Begriff Interkulturalität beizubehalten, da er seine Aktualität und Relevanz nicht verloren hat, wenn er auf die Ebene interpersonaler Interaktion bezogen wird. Denn gerade in Zeiten erhöhten Zuzugs in Gesellschaften kann es in interpersonellen Interaktionen vermehrt zu Erfahrungen von Differenz aufgrund unterschiedlicher Wissensbestände und Handlungsroutinen der Beteiligten kommen. Im Artikel wird vorgeschlagen, Interkulturalität als eine Perspektive der Interpretation interpersonaler Interaktion aufzufassen, die danach fragt, wie die Beteiligten kulturelle Differenz einbringen, inszenieren und erfahren. Mit Bezug auf das Konzept der Indexikalität wird anschließend darauf eingegangen, dass die sprachliche Darstellung von Interkulturalität immer eine unvermeidbare Tendenz zur Verallgemeinerung und damit zur (Re-)Produktion von Differenzlinien impliziert. Es wird dafür plädiert, diesem Dilemma mit einem bewussten Sprachgebrauch zu begegnen. The term interculturality is criticized for implying essentialist concepts of culture while ignoring the process of cultural hybridization in modern societies. In the light of the currently rising numbers of migrants, this issue seems to have become even more important. Has the term interculturality become obsolete or do we have to rethink it? This article argues that the term interculturality is still applicable and relevant, when referring to interpersonal interaction. In particular, increasing numbers of migrants in a society lead, in all probability, to interaction between people of different knowledge and routines, resulting in experiences of difference. In this article, the term interculturality is proposed as a perspective of interpreting interpersonal interaction focusing on how participants insert, constitute, and experience difference. Furthermore, referring to the concept of indexicality, the article highlights the fact that discussing interculturality always inevitably leads to generalization. The article proposes countering this dilemma by a conscious use of language

Perspective-reflexive language use in discussing interculturality

Dem Begriff Interkulturalität wird vorgeworfen, dass er eine raum-zeitliche Abgrenzbarkeit von Kulturen impliziere und die kulturelle Durchmischung moderner Gesellschaften nicht ausreichend berücksichtige. Diese Kritik scheint besonders vor dem Hintergrund der in der letzten Zeit sprunghaft angestiegenen Migrationsbewegungen an Aktualität zu gewinnen. Ist der Begriff also obsolet geworden oder müssen wir ihn neu denken? Der Artikel spricht sich dafür aus, den Begriff Interkulturalität beizubehalten, da er seine Aktualität und Relevanz nicht verloren hat, wenn er auf die Ebene interpersonaler Interaktion bezogen wird. Denn gerade in Zeiten erhöhten Zuzugs in Gesellschaften kann es in interpersonellen Interaktionen vermehrt zu Erfahrungen von Differenz aufgrund unterschiedlicher Wissensbestände und Handlungsroutinen der Beteiligten kommen. Im Artikel wird vorgeschlagen, Interkulturalität als eine Perspektive der Interpretation interpersonaler Interaktion aufzufassen, die danach fragt, wie die Beteiligten kulturelle Differenz einbringen, inszenieren und erfahren. Mit Bezug auf das Konzept der Indexikalität wird anschließend darauf eingegangen, dass die sprachliche Darstellung von Interkulturalität immer eine unvermeidbare Tendenz zur Verallgemeinerung und damit zur (Re-)Produktion von Differenzlinien impliziert. Es wird dafür plädiert, diesem Dilemma mit einem bewussten Sprachgebrauch zu begegnen. The term interculturality is criticized for implying essentialist concepts of culture while ignoring the process of cultural hybridization in modern societies. In the light of the currently rising numbers of migrants, this issue seems to have become even more important. Has the term interculturality become obsolete or do we have to rethink it? This article argues that the term interculturality is still applicable and relevant, when referring to interpersonal interaction. In particular, increasing numbers of migrants in a society lead, in all probability, to interaction between people of different knowledge and routines, resulting in experiences of difference. In this article, the term interculturality is proposed as a perspective of interpreting interpersonal interaction focusing on how participants insert, constitute, and experience difference. Furthermore, referring to the concept of indexicality, the article highlights the fact that discussing interculturality always inevitably leads to generalization. The article proposes countering this dilemma by a conscious use of language

Conductance through a Magnetic Domain Wall in Double Exchange System

The conductance through a magnetic domain wall is calculated for the double exchange system as a function of energy and the width of the domain wall. It is shown that when the carrier density is low enough, the blockade is almost complete even for the smoothly varying spin configuration, i.e., large width of the domain wall. This result is applied to the manganese oxides.Comment: 3 pages, LaTex, 1 Postscript figur

Transport and magnetic properties of La_(1-x)Ca_xMnO_3-films (0.1<x<0.9)

By laser ablation we prepared thin films of the colossal magnetoresistive compound La_(1-x)Ca_xMnO_3 with doping levels 0.1<x<0.9 on MgO substrates. X-ray diffraction revealed epitaxial growth and a systematic decrease of the lattice constants with doping. The variation of the transport and magnetic properties in this doping series was investigated by SQUID magnetization and electrical transport measurements. For the nonmetallic samples resistances up to 10^13 Ohm have been measured with an electrometer setup. While the transport data indicate polaronic transport for the metallic samples above the Curie temperature the low doped ferromagnetic insulating samples show a variable range hopping like transport at low temperature.Comment: 2 pages, 3 EPS figures, LT22 Proceedings to appear in Physica

Large negative magnetoresistance in thiospinel CuCrZrS4

We report on large negative magnetoresistance observed in ferromagnetic thiospinel compound CuCrZrS$_{4}$. Electrical resistivity increased with decreasing temperature according to the form proportional to $\textrm{exp}(T_{0}/T)^{1/2}$, derived from variable range hopping with strong electron-electron interaction. Resistivity under magnetic fields was expressed by the same form with the characteristic temperature T0 decreasing with increasing magnetic field. Magnetoresistance ratio $\rho (T,0)/\rho(T,H)$ is 1.5 at 100 K for H=90 kOe and increases divergently with decreasing temperature reaching 80 at 16 K. Results of magnetization measurements are also presented. Possible mechanism of the large magnetoresistance is discussed.Comment: 9 pages, 5 figures, to be published in Solid State Commu

Density Functional Theory of Magnetic Systems Revisited

The Hohenberg-Kohn theorem of density functional theory (DFT) for the case of electrons interacting with an external magnetic field (that couples to spin only) is examined in more detail than previously. A unexpected generalization is obtained: in certain cases (which include half metallic ferromagnets and magnetic insulators) the ground state, and hence the spin density matrix, is invariant for some non-zero range of a shift in uniform magnetic field. In such cases the ground state energy is not a functional of the spin density matrix alone. The energy gap in an insulator or a half metal is shown to be a ground state property of the N-electron system in magnetic DFT.Comment: Four pages, one figure. Submitted for publication, April 13, 2000 Revised, Sept 27, 200

Magneto and ferroelectric phase transitions in HoMn2O5 monocrystals

From the physical point of view multiferroics present an extremely interesting class of systems and problems. These are essentially of two kinds. One is what are the microscopic conditions, and sometimes constrains, which determine the possibility to combine in one system both magnetic and ferroelectric properties. This turned out to be a quite nontrivial question, and usually, in conventional systems, these two phenomena tend to exclude one another. Why it is the case is an important and still not completely resolved issue. In the present article we report our results from magnetic properties measurements on HoMn2O5 with short discussion about it possible origin

Low temperature resistivity in a nearly half-metallic ferromagnet

We consider electron transport in a nearly half-metallic ferromagnet, in which the minority spin electrons close to the band edge at the Fermi energy are Anderson-localized due to disorder. For the case of spin-flip scattering of the conduction electrons due to the absorption and emission of magnons, the Boltzmann equation is exactly soluble to the linear order. From this solution we calculate the temperature dependence of the resistivity due to single magnon processes at sufficiently low temperature, namely $k_BT\ll D/L^2$, where $L$ is the Anderson localization length and $D$ is the magnon stiffness. And depending on the details of the minority spin density of states at the Fermi level, we find a $T^{1.5}$ or $T^{2}$ scaling behavior for resistivity. Relevance to the doped perovskite manganite systems is discussed