Magnetic order in GdMnO3 in magnetic fields

Resonant magnetic x ray scattering at the Gd L2 edge is used to investigate the magnetic order of the Gd moments in multiferroic GdMnO3 at low temperatures. We present high magnetic field data on the magnetic ordering of Gd in the ferroelectric phase of GdMnO3. Our findings reaffirm the important role of the Gd moments in the symmetric magnetic exchange striction responsible for ferroelectricity in this compoun

Non-perturbative effects in a rapidly expanding quark-gluon plasma

Within first-order phase transitions, we investigate the pre-transitional effects due to the nonperturbative, large-amplitude thermal fluctuations which can promote phase mixing before the critical temperature is reached from above. In contrast with the cosmological quark-hadron transition, we find that the rapid cooling typical of the RHIC and LHC experiments and the fact that the quark-gluon plasma is chemically unsaturated suppress the role of non-perturbative effects at current collider energies. Significant supercooling is possible in a (nearly) homogeneous state of quark gluon plasma.Comment: LaTeX, 7 pages with 7 Postscript figures. Figures added, discussions added. Version to appear in Phys. Rev.

Modifications In Magnetic Properties Of Bimn2 O5 Multiferroic Using Swift Heavy Ion Irradiation

We report the near edge x-ray absorption fine structure (NEXAFS) and x-ray magnetic circular dichroism (XMCD) studies at the Mn L3,2 edge of pulsed laser deposited pristine thin films of multiferroic BiMn2 O5. These investigations are furthermore testified for BiMn2 O5 thin films irradiated through 200 MeV Ag15+ ions with fluence value 5× 1011 ions/ cm2. Though the pristine film is primarily antiferromagnetic in nature, irradiation induces ferrimagnetism in it. Element specific characterizations, NEXAFS and XMCD demonstrate the evolution of Mn2+ state piloting to magnetic signal associated with it. © 2010 American Institute of Physics.1079Nan, C.-W., Bichurin, M.I., Dong, S., Viehland, D., Srinivasan, G., Multiferroic magnetoelectric composites: Historical perspective, status, and future directions (2008) Journal of Applied Physics, 103 (3), p. 031101. , DOI 10.1063/1.2836410Ramesh, R., Spaldin, N.A., Multiferroics: Progress and prospects in thin films (2007) Nature Materials, 6 (1), pp. 21-29. , DOI 10.1038/nmat1805, PII NMAT1805Eerenstein, W., Mathur, N.D., Scott, J.F., Multiferroic and magnetoelectric materials (2006) Nature, 442 (7104), pp. 759-765. , DOI 10.1038/nature05023, PII NATURE05023Gajek, M., Bibes, M., Fusil, S., Bouzehouane, K., Fontcuberta, J., Barthelemy, A., Fert, A., Tunnel junctions with multiferroic barriers (2007) Nature Materials, 6 (4), pp. 296-302. , DOI 10.1038/nmat1860, PII NMAT1860Cheong, S.-W., Mostovoy, M., Multiferroics: A magnetic twist for ferroelectricity (2007) Nature Materials, 6 (1), pp. 13-20. , DOI 10.1038/nmat1804, PII NMAT1804Hur, N., Park, S., Sharma, P.A., Ahn, J.S., Guha, S., Cheong, S.-W., Electric polarization reversal and memory in a multiferroic material induced by magnetic fields (2004) Nature, 429 (6990), pp. 392-395. , DOI 10.1038/nature02572Chapon, L.C., Radaelli, P.G., Blake, G.R., Park, S., Cheong, S.-W., Ferroelectricity induced by acentric spin-density waves in YMn2O5 (2006) Physical Review Letters, 96 (9), pp. 1-4. , http://oai.aps.org/oai?verb=GetRecord&Identifier=oai:aps.org: PhysRevLett.96.097601&metadataPrefix=oai_apsmeta_2, DOI 10.1103/PhysRevLett.96.097601, 097601Muoz, A., Alonso, J.A., Casais, M.T., Martínez-Lope, M.J., Martínez, J.L., Fernández-Díaz, M.T., (2002) Phys. Rev. B, 65, p. 144423. , PRBMDO 0163-1829,. 10.1103/PhysRevB.65.144423Blake, G.R., Chapon, L.C., Radaelli, P.G., Park, S., Hur, N., Cheong, S.-W., Rodriguez-Carvajal, J., Spin structure and magnetic frustration in multiferroic RMn2O5 (R=Tb,Ho,Dy) (2005) Physical Review B - Condensed Matter and Materials Physics, 71 (21), pp. 1-9. , http://oai.aps.org/oai/?verb=ListRecords&metadataPrefix= oai_apsmeta_2&set=journal:PRB:71, DOI 10.1103/PhysRevB.71.214402, 214402Shukla, D.K., Kumar, R., Sharma, S.K., Thakur, P., Choudhary, R.J., Mollah, S., Brookes, N.B., Choi, W.K., (2009) J. Phys. D, 42, p. 125304. , JPAPBE 0022-3727,. 10.1088/0022-3727/42/12/125304Vecchini, C., Chapon, L.C., Brown, P.J., Chatterji, T., Park, S., Cheong, S.W., Radaelli, P.G., (2008) Phys. Rev. B, 77, p. 134434. , PRBMDO 0163-1829,. 10.1103/PhysRevB.77.134434Shukla, D.K., Mollah, S., Kumar, R., Thakur, P., Chae, K.H., Banerjee, A., Choi, W.K., (2008) J. Appl. Phys., 104, p. 033707. , JAPIAU 0021-8979,. 10.1063/1.2964072Kumar, R., Arora, S.K., Kanjilal, D., Mehta, G.K., Bache, R., Date, S.K., Shinde, S.R., Patil, S.I., (1999) Radiat. Eff. Defects Solids, 147, p. 187. , REDSEI 1042-0150,. 10.1080/10420159908229008Houpert, C., Studer, F., Groult, D., Toulmonde, M., (1989) Nucl. Instrum. Methods Phys. Res. B, 39, p. 720. , NIMBEU 0168-583X,. 10.1016/0168-583X(89)90882-3Kumar, R., Samantra, S.B., Arora, S.K., Gupta, A., Kanjilal, D., Pinto, R., Narlikar, A.V., (1998) Solid State Commun., 106, p. 805. , SSCOA4 0038-1098,. 10.1016/S0038-1098(98)00122-7Biersack, J.P., Haggmark, L., (1980) Nucl. Instrum. Methods Phys. Res., 174, p. 257. , NIMRD9 0167-5087,. 10.1016/0029-554X(80)90440-1Shukla, D.K., unpublished dataWang, Z.G., Dufour, C., Paumier, E., Toulemonde, M., (1994) J. Phys.: Condens. Matter, 6, p. 6733. , JCOMEL 0953-8984,. 10.1088/0953-8984/6/34/006Izui, K., Furuno, S., (1986) Proceedings of the 11th International Congress on Electron Microscopy, p. 1299. , edited by T. Imura, S. Maruse, and T. Suzuki (Japanese Society of Electron Microscopy, Tokyo),Meftah, A., Brisard, F., Costantini, J.M., Hage-Ali, M., Stoquert, J.P., Studer, F., Toulemonde, M., (1993) Phys. Rev. B, 48, p. 920. , and, PRBMDO 0163-1829,. 10.1103/PhysRevB.48.920Thibaudau, F., Cousty, J., Balanzat, E., Bouffard, S., (1991) Phys. Rev. Lett., 67, p. 1582. , PRLTAO 0031-9007,. 10.1103/PhysRevLett.67.1582Toulemonde, M., Dufour, C., Paumier, E., (1992) Phys. Rev. B, 46, p. 14362. , PRBMDO 0163-1829,. 10.1103/PhysRevB.46.1436

Activation Energy in a Quantum Hall Ferromagnet and Non-Hartree-Fock Skyrmions

The energy of Skyrmions is calculated with the help of a technique based on the excitonic representation: the basic set of one-exciton states is used for the perturbation-theory formalism instead of the basic set of one-particle states. We use the approach, at which a skyrmion-type excitation (at zero Lande factor) is considered as a smooth non-uniform rotation in the 3D spin space. The result within the framework of an excitonically diagonalized part of the Coulomb Hamiltonian can be obtained by any ratio $r_{\tiny C}=(e^2/\epsilon {}l_B)/\hbar \omega_c$ [where $e^2/\epsilon {}l_B$ is the typical Coulomb energy (${}l_B$ being the magnetic length); $\omega_c$ is the cyclotron frequency], and the Landau-level mixing is thereby taken into account. In parallel with this, the result is also found exactly, to second order in terms of the $r_{\tiny C}$ (if supposing $r_{\tiny C}$ to be small) with use of the total Hamiltonian. When extrapolated to the region $r_{\tiny C}\sim 1$, our calculations show that the skyrmion gap becomes substantially reduced in comparison with the Hartree-Fock calculations. This fact brings the theory essentially closer to the available experimental data.Comment: 14 pages, 1 figure. to appear in Phys. Rev. B, Vol. 65 (Numbers ~ 19-22), 200

The Effects of Disorder on the ν=1\nu=1 Quantum Hall State

A disorder-averaged Hartree-Fock treatment is used to compute the density of single particle states for quantum Hall systems at filling factor $\nu=1$. It is found that transport and spin polarization experiments can be simultaneously explained by a model of mostly short-range effective disorder. The slope of the transport gap (due to quasiparticles) in parallel field emerges as a result of the interplay between disorder-induced broadening and exchange, and has implications for skyrmion localization.Comment: 4 pages, 3 eps figure

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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