Spin-flop transitions and spin-wave gaps in La_2CuO_4

We study the spin-wave spectrum and the spin-flop transitions in La_2CuO_4 in a uniform magnetic field at zero temperature. Using the non-linear sigma-model, we show that a field applied along the orthorhombic b direction leads to a two-step rotation of the staggered magnetization, first in the bc and then in the ac plane, until the order parameter is completely aligned along the c axis. In contrast, for a perpendicular magnetic field, we find a conventional spin-flop transition induced by the competition between the field and the interlayer coupling. A comparison with recent measurements of the field-dependence of the in-plane spin-wave gap shows a beautiful agreement between theory and experiments.Comment: 7 pages, 3 figures; added referenc

Bi-quadratic magnetoelectric coupling in underdoped La_2CuO_{4+x}

The recent discovery of relaxor ferroelectricity and magnetoelectric effect in lightly doped cuprate material La_2CuO_{4+x} has provided a number of questions concerning its theoretical description. It has been argued using a Ginzburg-Landau free energy approach that the magnetoelectric effect can be explained by the presence of bi-quadratic interaction terms in the free energy. Here, by using the same free energy functional, we study the variety of behavior which can emerge in the electric polarization under an external magnetic field. Subsequently, we discuss the role of Dzyaloshinskii-Moriya interaction in generating this magnetoelectric response. This work is particularly relevant for such relaxor systems where the material-dependent parameters would be affected by changes in e.g. chemical doping or cooling rate.Comment: 8 pages, 2 figures. arXiv admin note: text overlap with arXiv:1112.152

Comment on "Strong dependence of the interlayer coupling on the hole mobility in antiferromagnetic La2−x_{2-x}Srx_xCuO4_4 (x<0.02x<0.02)"

Using the experimental data given in Phys. Rev. B70, 220507 (2004), we show that -- unlike the effective coupling discussed in this paper -- the net average antiferromagnetic interlayer coupling in doped lanthanum cuprates depends only weakly on the doping or on the temperature. We argue that the effective coupling is proportional to the square of the staggered magnetization, and does not supply new information about the origin of the suppression of the magnetic order in doped samples. Our analysis is based on a modified version of the equation describing the spin-flip transition, which takes into account the decrease of the staggered moment with temperature and doping.Comment: Phys. Rev. B (in press

Pengaruh Kebijakan Dividen, Likuiditas, Net Profit Margin, Return on Equity, Dan Price to Book Value Terhadap Harga Saham Pada Perusahaan Manufaktur Yang Terdaftar Di Bursa Efek Indonesia 2010 – 2013

This research aimed to analyze the effect of Dividend Policy, Liquidity,NPM, ROE, and PBV on stock prices of manufacturing companies in 2010 &ndash; 2013.Samples were manufacturing companies that listed in Indonesia Stock Exchange in2010 &ndash; 2013. This research uses 72 data with 18 selected companies per year. Theanalysis tool used in this research is multiple linear regression using SPSS computerprogram version 21.0. The results show that Dividend Policy, Liquidity, NPM, ROE,and PBV jointly have significantly affected the stock price. Partially, Dividend Policyhave significantly affected the stock price, whereas Liquidity, NPM, ROE, and PBVhave not significantly affected the stock price

Pengaruh Ukuran Perusahaan, Ukuran Dewan Komisaris, Profitabilitas Dan Leverage Terhadap Pengungkapan Tanggung Jawab Sosial Pada Perusahaan Manufaktur Yang Terdaftar Di Bei

This study aims to obtain empirical evidence of the effect of firm size, the size of the board of commissioners, profitability and leverage on the disclosure of social responsibility in manufacturing companies on the Stock Exchange in 2009-2011, as well as answers to some of the results of previous research gaps regarding the effect of firm size, the size of the board of commissioners , profitability and leverage on the disclosure of corporate social responsibility.This study uses financial statement data of manufacturing firms during the period 2009-2011. Analysis tools are used to examine the effect of the variables in this study were the F test (ANOVA) for simultaneous testing of multiple regression equations and partial t test to test each variable X to variable Y. Besides, to see how much the contribution of each variable used Adjusted R square. Overall analysis using SPPS program.The results showed that of the test or ANOVA F test, indicating the size of the company, the size of the board of commissioners, profitability and simultaneously leverage effect on social responsibility disclosure in manufacturing companies on the Stock Exchange in 2009-2011 with 95% confidence level. Then from the partial test results using the t test is known that only firm size and profitability have a significant influence on the disclosure of social responsibility, while the size of the board of commissioners and leverage does not have a significant effect on the disclosure of social responsibility. This research is &nbsp;expected to provide an overview and understanding of the relationship of corporate social responsibility disclosure

Frustration of the interlayer coupling by mobile holes in La2-xSrxCuO4 (x<0.02)

We have studied the interlayer coupling in the antiferromagnetic (AF) phase of Sr and Zn doped La2CuO4 by analyzing the spin flip transition in the magnetization curves. We find that the interlayer coupling strongly depends on the mobility of the hole charge carriers. Samples with the same hole content as well as the same Neel temperature but a different hole mobility, which we adjusted by Zn co-doping, can have a very different interlayer coupling. Our results suggest that only mobile holes can cause a strong frustration of the interlayer coupling.Comment: 4 pages, 4 figure

Magnetic susceptibility anisotropies in a two-dimensional quantum Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions

The magnetic and thermodynamic properties of the two-dimensional quantum Heisenberg antiferromagnet that incorporates both a Dzyaloshinskii-Moriya and pseudo-dipolar interactions are studied within the framework of a generalized nonlinear sigma model (NLSM). We calculate the static uniform susceptibility and sublattice magnetization as a function of temperature and we show that: i) the magnetic-response is anisotropic and differs qualitatively from the expected behavior of a conventional easy-axis QHAF; ii) the Neel second-order phase transition becomes a crossover, for a magnetic field B perpendicular to the CuO(2) layers. We provide a simple and clear explanation for all the recently reported unusual magnetic anisotropies in the low-field susceptibility of La(2)CuO(4), L. N. Lavrov et al., Phys. Rev. Lett. 87, 017007 (2001), and we demonstrate explicitly why La(2)CuO(4) can not be classified as an ordinary easy-axis antiferromagnet.Comment: 6 pages, 3 figures, Revtex4, accepted for publication in Phys. Rev.

Pengaruh Motivasi dan Kepemimpinan terhadap Kepuasan Kerja Karyawan pada PT. Adira Finance Cabang Pekanbaru

Formulation of the problem in writing this essay is What motivation and leadership simultaneously affect the job satisfaction of employees at PT Adira Finance Cabang Pekanbaru? Is partial motivation affect the job satisfaction of employees at PT Adira Finance Cabang Pekanbaru? Is leadership a partial effect on job satisfaction of employees at PT Adira Finance Cabang Pekanbaru? The population of this study were employees of PT Adira Finance Cabang Pekanbaru, amounting to 268 people. In Slovin sampling method is used to obtain as many as 71 respondents. To determine the perceptions of the dimensions of job satisfaction, the method of data analysis used in this study is using the method of Multiple Linear Regression, F test and t test. Results of research and testing simultaneously known simultaneously, variable motivation , leadership significant effect on satisfaction. There are indicators with an average low of leadership and employee relationships, where employees feel a lack of harmony in the relationship between leaders and subordinates. The results of the study partially motivated significant effect on employee job satisfaction. Motivation in the form of superiors to subordinates approach has not been felt by employees, especially supervisors indifference. In addition, awards to employees who do not perform. Thus, employees who have no achievements strive to continually improve performance resulting into decreased job satisfaction. The results of the research for leadership variables partially significant effect on employee job satisfaction. Low motivation of employees in marketing products proactively savings, lack of initiative, and are still waiting for not doing proactive strategy. If this is allowed to continue would result in a decrease of performance appraisal which impact on the compensation received by the employee so as to reduce employee job satisfaction

Local spin spirals in the Neel phase of La_{2-x}Sr_xCuO_4

Experimental observations of lightly doped La_{2-x}Sr_xCuO_4, x < 0.02, revealed remarkable magnetic properties such as the incommensurate noncollinear ordering (additional to the Neel ordering) and a tremendous doping dependence of the uniform longitudinal susceptibility. We show that the spiral solution of the t-t'-t''-J model obtained by taking into account the Coulomb trapping of holes by Sr ions describes these puzzling data perfectly well. Our solution firstly explains why the incommensurate structure is directed along the orthorhombic b-axis, and secondly allows a numerical calculation of the positions and shapes of the incommensurate neutron scattering peaks. Thirdly, we calculate the doping dependence of the spin-wave gap, and lastly, we study the longitudinal magnetic susceptibility and show that its doping dependence is due to the noncollinearity of the spin spiral.Comment: 13 pages, 8 figure

Strong Discontinuities in the Complex Photonic Band Structure of Transmission Metallic Gratings

Complex photonic band structures (CPBS) of transmission metallic gratings with rectangular slits are shown to exhibit strong discontinuities that are not evidenced in the usual energetic band structures. These discontinuities are located on Wood's anomalies and reveal unambiguously two different types of resonances, which are identified as horizontal and vertical surface-plasmon resonances. Spectral position and width of peaks in the transmission spectrum can be directly extracted from CPBS for both kinds of resonances.Comment: 4 pages, 4 figures, REVTeX version